answer
string
choices
dict
id
string
kind
string
lang
string
question
string
steps
list
subject
string
text
string
topic
string
It composes linear maps via row-column dot products, and order matters since maps differ.
null
mat_0051
concept
en
What is matrix multiplication?
[ "It composes linear maps via row-column dot products, and order matters since maps differ.", "So the answer stands: It composes linear maps via row-column dot products, and order matters since maps differ." ]
math
Answer: It composes linear maps via row-column dot products, and order matters since maps differ. Steps: 1. It composes linear maps via row-column dot products, and order matters since maps differ. 2. So the answer stands: It composes linear maps via row-column dot products, and order matters since maps differ.
linear_algebra
Independent events multiply probabilities, since one's outcome never affects the other's.
null
mat_0052
concept
en
What is independence?
[ "Independent events multiply probabilities, since one's outcome never affects the other's.", "So the answer stands: Independent events multiply probabilities, since one's outcome never affects the other's." ]
math
Answer: Independent events multiply probabilities, since one's outcome never affects the other's. Steps: 1. Independent events multiply probabilities, since one's outcome never affects the other's. 2. So the answer stands: Independent events multiply probabilities, since one's outcome never affects the other's.
probability
Zbytek je 1.
{ "A": "2", "B": "1", "C": "3", "D": "4" }
mat_0053
multiple_choice
cs
Vypočítej (100) mod 9.
[ "100 ÷ 9.", "Zbytek 1.", "Vyber možnost B." ]
math
Answer: 1 Steps: 1. 100 ÷ 9. 2. Zbytek 1. 3. Vyber možnost B. Answer: (B)
number_theory
C(5,3) is 10.
{ "A": "5", "B": "15", "C": "10", "D": "20" }
mat_0054
multiple_choice
en
Compute C(5,3).
[ "5×4×3/6.", "= 10.", "Select option C." ]
math
Answer: 10 Steps: 1. 5×4×3/6. 2. = 10. 3. Select option C. Answer: (C)
combinatorics
Induction proves a base case and shows each case implies the next, so the claim holds for all natural numbers.
null
mat_0055
concept
en
What is induction?
[ "Induction proves a base case and shows each case implies the next, so the claim holds for all natural numbers.", "So the answer stands: Induction proves a base case and shows each case implies the next, so the claim holds for all natural numbers." ]
math
Answer: Induction proves a base case and shows each case implies the next, so the claim holds for all natural numbers. Steps: 1. Induction proves a base case and shows each case implies the next, so the claim holds for all natural numbers. 2. So the answer stands: Induction proves a base case and shows each case implie...
proofs
Limit: 8.
null
mat_0056
worked_example
en
Evaluate the limit of (x² − 4²)/(x − 4) as x → 4.
[ "Factor: (x−4)(x+4).", "Cancel (x−4).", "Plug 4: 4+4 = 8." ]
math
Answer: Limit: 8. Steps: 1. Factor: (x−4)(x+4). 2. Cancel (x−4). 3. Plug 4: 4+4 = 8.
calculus
The dot product is 11.
{ "A": "7", "B": "15", "C": "11", "D": "19" }
mat_0057
multiple_choice
en
Find the dot product (1,2) · (3,4).
[ "1×3 + 2×4.", "Product = 11.", "Select option C." ]
math
Answer: 11 Steps: 1. 1×3 + 2×4. 2. Product = 11. 3. Select option C. Answer: (C)
linear_algebra
P = 1/7.
null
mat_0058
worked_example
en
A fair 7-sided die is rolled. Show P(one specific number).
[ "Favourable: 1.", "Possible: 7.", "P = 1/7." ]
math
Answer: P = 1/7. Steps: 1. Favourable: 1. 2. Possible: 7. 3. P = 1/7.
probability
gcd = 4.
null
mat_0059
worked_example
en
Compute gcd(8, 12) step by step.
[ "Factor: 8=4×2, 12=6×2.", "Common: 2×gcd(4,6).", "= 2×2 = 4." ]
math
Answer: gcd = 4. Steps: 1. Factor: 8=4×2, 12=6×2. 2. Common: 2×gcd(4,6). 3. = 2×2 = 4.
number_theory
P(5,3) = 60.
null
mat_0060
worked_example
en
Show the computation of P(5,3).
[ "n(n−1)(n−2).", "5×4×3.", "= 60." ]
math
Answer: P(5,3) = 60. Steps: 1. n(n−1)(n−2). 2. 5×4×3. 3. = 60.
combinatorics
Half: 6, so 12 is even.
null
mat_0061
worked_example
en
Show N² + N is even for N = 3 by computing its half.
[ "3² + 3 = 12.", "12 / 2 = 6.", "Integer, so even." ]
math
Answer: Half: 6, so 12 is even. Steps: 1. 3² + 3 = 12. 2. 12 / 2 = 6. 3. Integer, so even.
proofs
The derivative is 4.
{ "A": "4", "B": "2", "C": "6", "D": "8" }
mat_0062
multiple_choice
en
For f(x) = 1x² + 2x, find f'(1).
[ "f'(x) = 2x + 2.", "At 1: 4.", "Select option A." ]
math
Answer: 4 Steps: 1. f'(x) = 2x + 2. 2. At 1: 4. 3. Select option A. Answer: (A)
calculus
The answer is Nonzero determinant.
{ "A": "Big entries", "B": "Round shape", "C": "Long name", "D": "Nonzero determinant" }
mat_0063
multiple_choice
en
Choose: what detects invertibility?
[ "Zero means collapse.", "So: Nonzero determinant.", "Select option D." ]
math
Answer: Nonzero determinant Steps: 1. Zero means collapse. 2. So: Nonzero determinant. 3. Select option D. Answer: (D)
linear_algebra
Expectation averages outcomes by probability, predicting long-run results of gambles.
null
mat_0064
concept
en
Why expected value?
[ "Expectation averages outcomes by probability, predicting long-run results of gambles.", "So the answer stands: Expectation averages outcomes by probability, predicting long-run results of gambles." ]
math
Answer: Expectation averages outcomes by probability, predicting long-run results of gambles. Steps: 1. Expectation averages outcomes by probability, predicting long-run results of gambles. 2. So the answer stands: Expectation averages outcomes by probability, predicting long-run results of gambles.
probability
Euclid multiplies known primes and adds one, forcing a new prime factor each time.
null
mat_0065
concept
en
Why infinitely many primes?
[ "Euclid multiplies known primes and adds one, forcing a new prime factor each time.", "So the answer stands: Euclid multiplies known primes and adds one, forcing a new prime factor each time." ]
math
Answer: Euclid multiplies known primes and adds one, forcing a new prime factor each time. Steps: 1. Euclid multiplies known primes and adds one, forcing a new prime factor each time. 2. So the answer stands: Euclid multiplies known primes and adds one, forcing a new prime factor each time.
number_theory
C(7,3) = 35.
null
mat_0066
worked_example
en
Show the computation of C(7,3).
[ "n(n−1)(n−2)/6.", "7×6×5/6.", "= 35." ]
math
Answer: C(7,3) = 35. Steps: 1. n(n−1)(n−2)/6. 2. 7×6×5/6. 3. = 35.
combinatorics
The base case anchors induction, because without a true start the chain of implications proves nothing.
null
mat_0067
concept
en
Why prove the base case?
[ "The base case anchors induction, because without a true start the chain of implications proves nothing.", "So the answer stands: The base case anchors induction, because without a true start the chain of implications proves nothing." ]
math
Answer: The base case anchors induction, because without a true start the chain of implications proves nothing. Steps: 1. The base case anchors induction, because without a true start the chain of implications proves nothing. 2. So the answer stands: The base case anchors induction, because without a true start the cha...
proofs
The integral is 8.
{ "A": "6", "B": "8", "C": "10", "D": "12" }
mat_0068
multiple_choice
en
Compute the integral of 3x² from 0 to 2.
[ "Antiderivative x³.", "2³ = 8.", "Select option B." ]
math
Answer: 8 Steps: 1. Antiderivative x³. 2. 2³ = 8. 3. Select option B. Answer: (B)
calculus
The determinant scales volumes and detects invertibility, with zero meaning collapse to lower dimension.
null
mat_0069
concept
en
Why care about determinant?
[ "The determinant scales volumes and detects invertibility, with zero meaning collapse to lower dimension.", "So the answer stands: The determinant scales volumes and detects invertibility, with zero meaning collapse to lower dimension." ]
math
Answer: The determinant scales volumes and detects invertibility, with zero meaning collapse to lower dimension. Steps: 1. The determinant scales volumes and detects invertibility, with zero meaning collapse to lower dimension. 2. So the answer stands: The determinant scales volumes and detects invertibility, with zero...
linear_algebra
E = 3.5.
null
mat_0070
worked_example
en
Compute E of a uniform draw from {1..6}.
[ "Mean of 1..6.", "(6+1)/2.", "E = 3.5." ]
math
Answer: E = 3.5. Steps: 1. Mean of 1..6. 2. (6+1)/2. 3. E = 3.5.
probability
Remainder: 1.
null
mat_0071
worked_example
en
Compute (50) mod 7.
[ "Divide 50 by 7.", "7×7 = 49.", "50 − 49 = 1." ]
math
Answer: Remainder: 1. Steps: 1. Divide 50 by 7. 2. 7×7 = 49. 3. 50 − 49 = 1.
number_theory
C(7,2) = 21.
null
mat_0072
worked_example
en
Show the computation of C(7,2).
[ "Formula n(n−1)/2.", "7×6/2.", "= 21." ]
math
Answer: C(7,2) = 21. Steps: 1. Formula n(n−1)/2. 2. 7×6/2. 3. = 21.
combinatorics
Tabulka má 4 řádků.
{ "A": "4", "B": "2", "C": "6", "D": "8" }
mat_0073
multiple_choice
cs
Kolik řádků má pravdivostní tabulka s 2 proměnnými?
[ "2^2 řádků.", "Celkem: 4.", "Vyber možnost A." ]
math
Answer: 4 Steps: 1. 2^2 řádků. 2. Celkem: 4. 3. Vyber možnost A. Answer: (A)
proofs
A derivative is the instantaneous rate of change, giving the slope of the tangent line at each point.
null
mat_0074
concept
en
What is a derivative?
[ "A derivative is the instantaneous rate of change, giving the slope of the tangent line at each point.", "So the answer stands: A derivative is the instantaneous rate of change, giving the slope of the tangent line at each point." ]
math
Answer: A derivative is the instantaneous rate of change, giving the slope of the tangent line at each point. Steps: 1. A derivative is the instantaneous rate of change, giving the slope of the tangent line at each point. 2. So the answer stands: A derivative is the instantaneous rate of change, giving the slope of the...
calculus
Dot product: 11.
null
mat_0075
worked_example
en
Compute (2,1) · (3,5) step by step.
[ "Multiply components.", "2×3 + 1×5.", "= 11." ]
math
Answer: Dot product: 11. Steps: 1. Multiply components. 2. 2×3 + 1×5. 3. = 11.
linear_algebra
P(red) = 4/8.
null
mat_0076
worked_example
en
A bag holds 4 red and 4 blue marbles. Show P(red).
[ "Red: 4.", "Total: 8.", "P = 4/8." ]
math
Answer: P(red) = 4/8. Steps: 1. Red: 4. 2. Total: 8. 3. P = 4/8.
probability
The lcm is 12.
{ "A": "10", "B": "14", "C": "12", "D": "16" }
mat_0077
multiple_choice
en
Find lcm(4, 6).
[ "4×6/gcd.", "lcm = 12.", "Select option C." ]
math
Answer: 12 Steps: 1. 4×6/gcd. 2. lcm = 12. 3. Select option C. Answer: (C)
number_theory
P(6,3) = 120.
null
mat_0078
worked_example
en
Show the computation of P(6,3).
[ "n(n−1)(n−2).", "6×5×4.", "= 120." ]
math
Answer: P(6,3) = 120. Steps: 1. n(n−1)(n−2). 2. 6×5×4. 3. = 120.
combinatorics
Součet: 21.
null
mat_0079
worked_example
cs
Dokaž vzorcem: najdi součet 1 + 2 + ... + 6.
[ "Páruj 1+6, 2+5, ...", "Použij 6×7/2.", "= 21." ]
math
Answer: Součet: 21. Steps: 1. Páruj 1+6, 2+5, ... 2. Použij 6×7/2. 3. = 21.
proofs
Integrál je 8.
{ "A": "6", "B": "8", "C": "10", "D": "12" }
mat_0080
multiple_choice
cs
Vypočítej integrál 3x² od 0 do 2.
[ "Primitivní x³.", "2³ = 8.", "Vyber možnost B." ]
math
Answer: 8 Steps: 1. Primitivní x³. 2. 2³ = 8. 3. Vyber možnost B. Answer: (B)
calculus
Determinant: 10.
null
mat_0081
worked_example
en
Compute det [[3,1],[2,4]] step by step.
[ "ad − bc.", "3×4 − 1×2.", "= 10." ]
math
Answer: Determinant: 10. Steps: 1. ad − bc. 2. 3×4 − 1×2. 3. = 10.
linear_algebra
Variance averages squared deviations, measuring how spread out a random variable is.
null
mat_0082
concept
en
What is variance?
[ "Variance averages squared deviations, measuring how spread out a random variable is.", "So the answer stands: Variance averages squared deviations, measuring how spread out a random variable is." ]
math
Answer: Variance averages squared deviations, measuring how spread out a random variable is. Steps: 1. Variance averages squared deviations, measuring how spread out a random variable is. 2. So the answer stands: Variance averages squared deviations, measuring how spread out a random variable is.
probability
The greatest common divisor is the largest integer dividing both numbers at once.
null
mat_0083
concept
en
What is the gcd?
[ "The greatest common divisor is the largest integer dividing both numbers at once.", "So the answer stands: The greatest common divisor is the largest integer dividing both numbers at once." ]
math
Answer: The greatest common divisor is the largest integer dividing both numbers at once. Steps: 1. The greatest common divisor is the largest integer dividing both numbers at once. 2. So the answer stands: The greatest common divisor is the largest integer dividing both numbers at once.
number_theory
C(8,3) = 56.
null
mat_0084
worked_example
en
Show the computation of C(8,3).
[ "n(n−1)(n−2)/6.", "8×7×6/6.", "= 56." ]
math
Answer: C(8,3) = 56. Steps: 1. n(n−1)(n−2)/6. 2. 8×7×6/6. 3. = 56.
combinatorics
The value is 12.
{ "A": "10", "B": "14", "C": "12", "D": "16" }
mat_0085
multiple_choice
en
Compute N² + N for N = 3.
[ "3² + 3.", "Value = 12.", "Select option C." ]
math
Answer: 12 Steps: 1. 3² + 3. 2. Value = 12. 3. Select option C. Answer: (C)
proofs
The limit is 4.
{ "A": "2", "B": "6", "C": "4", "D": "8" }
mat_0086
multiple_choice
en
Find the limit of (x² − 2²)/(x − 2) as x → 2.
[ "Factor (x−2)(x+2).", "Cancel, get 2×2 = 4.", "Select option C." ]
math
Answer: 4 Steps: 1. Factor (x−2)(x+2). 2. Cancel, get 2×2 = 4. 3. Select option C. Answer: (C)
calculus
Trace: 9.
null
mat_0087
worked_example
en
Compute the trace of [[4,0],[0,5]].
[ "Sum diagonal.", "4 + 5.", "= 9." ]
math
Answer: Trace: 9. Steps: 1. Sum diagonal. 2. 4 + 5. 3. = 9.
linear_algebra
The expected value is 2.5.
{ "A": "3.5", "B": "2.5", "C": "1.5", "D": "4.5" }
mat_0088
multiple_choice
en
Find the expected value of a uniform draw from {1..4}.
[ "(4+1)/2.", "E = 2.5.", "Select option B." ]
math
Answer: 2.5 Steps: 1. (4+1)/2. 2. E = 2.5. 3. Select option B. Answer: (B)
probability
The answer is Primes.
{ "A": "Evens", "B": "Squares", "C": "Cubes", "D": "Primes" }
mat_0089
multiple_choice
en
Choose: what are multiplication atoms?
[ "Unique factorization.", "So: Primes.", "Select option D." ]
math
Answer: Primes Steps: 1. Unique factorization. 2. So: Primes. 3. Select option D. Answer: (D)
number_theory
The answer is Factorial.
{ "A": "Sum", "B": "Average", "C": "Guess", "D": "Factorial" }
mat_0090
multiple_choice
en
Choose: what counts orderings?
[ "Choices shrink per slot.", "So: Factorial.", "Select option D." ]
math
Answer: Factorial Steps: 1. Choices shrink per slot. 2. So: Factorial. 3. Select option D. Answer: (D)
combinatorics
A counterexample is one case where a universal claim fails, and a single one disproves the whole claim.
null
mat_0091
concept
en
What is a counterexample?
[ "A counterexample is one case where a universal claim fails, and a single one disproves the whole claim.", "So the answer stands: A counterexample is one case where a universal claim fails, and a single one disproves the whole claim." ]
math
Answer: A counterexample is one case where a universal claim fails, and a single one disproves the whole claim. Steps: 1. A counterexample is one case where a universal claim fails, and a single one disproves the whole claim. 2. So the answer stands: A counterexample is one case where a universal claim fails, and a sin...
proofs
f'(4) = 35.
null
mat_0092
worked_example
en
For f(x) = 4x² + 3x, compute f'(4) step by step.
[ "f'(x) = 8x + 3.", "Plug x = 4.", "8×4 + 3 = 35." ]
math
Answer: f'(4) = 35. Steps: 1. f'(x) = 8x + 3. 2. Plug x = 4. 3. 8×4 + 3 = 35.
calculus
Rank counts independent rows or columns, measuring the true dimension of the map's image.
null
mat_0093
concept
en
What is rank?
[ "Rank counts independent rows or columns, measuring the true dimension of the map's image.", "So the answer stands: Rank counts independent rows or columns, measuring the true dimension of the map's image." ]
math
Answer: Rank counts independent rows or columns, measuring the true dimension of the map's image. Steps: 1. Rank counts independent rows or columns, measuring the true dimension of the map's image. 2. So the answer stands: Rank counts independent rows or columns, measuring the true dimension of the map's image.
linear_algebra
P(red) is 2/7.
{ "A": "5/7", "B": "2/8", "C": "2/7", "D": "3/7" }
mat_0094
multiple_choice
en
A bag holds 2 red and 5 blue marbles. What is P(red)?
[ "2 of 7.", "P = 2/7.", "Select option C." ]
math
Answer: 2/7 Steps: 1. 2 of 7. 2. P = 2/7. 3. Select option C. Answer: (C)
probability
Repeated remainders shrink the pair fast, computing gcds in logarithmic steps.
null
mat_0095
concept
en
Why Euclid's algorithm?
[ "Repeated remainders shrink the pair fast, computing gcds in logarithmic steps.", "So the answer stands: Repeated remainders shrink the pair fast, computing gcds in logarithmic steps." ]
math
Answer: Repeated remainders shrink the pair fast, computing gcds in logarithmic steps. Steps: 1. Repeated remainders shrink the pair fast, computing gcds in logarithmic steps. 2. So the answer stands: Repeated remainders shrink the pair fast, computing gcds in logarithmic steps.
number_theory
nCr counts subsets of size r from n objects, ignoring order via division by r!.
null
mat_0096
concept
en
What is nCr?
[ "nCr counts subsets of size r from n objects, ignoring order via division by r!.", "So the answer stands: nCr counts subsets of size r from n objects, ignoring order via division by r!." ]
math
Answer: nCr counts subsets of size r from n objects, ignoring order via division by r!. Steps: 1. nCr counts subsets of size r from n objects, ignoring order via division by r!. 2. So the answer stands: nCr counts subsets of size r from n objects, ignoring order via division by r!.
combinatorics
The answer is Base case.
{ "A": "Fancy notation", "B": "Long chains", "C": "Big numbers", "D": "Base case" }
mat_0097
multiple_choice
en
Choose: what anchors induction?
[ "Without base, chain proves nothing.", "So: Base case.", "Select option D." ]
math
Answer: Base case Steps: 1. Without base, chain proves nothing. 2. So: Base case. 3. Select option D. Answer: (D)
proofs
Integral: 125.
null
mat_0098
worked_example
en
Evaluate the integral of 3x² from 0 to 5.
[ "Antiderivative: x³.", "Evaluate 0 to 5.", "5³ − 0 = 125." ]
math
Answer: Integral: 125. Steps: 1. Antiderivative: x³. 2. Evaluate 0 to 5. 3. 5³ − 0 = 125.
calculus
Row reduction exposes pivots and solutions, solving linear systems mechanically every time.
null
mat_0099
concept
en
Why row-reduce?
[ "Row reduction exposes pivots and solutions, solving linear systems mechanically every time.", "So the answer stands: Row reduction exposes pivots and solutions, solving linear systems mechanically every time." ]
math
Answer: Row reduction exposes pivots and solutions, solving linear systems mechanically every time. Steps: 1. Row reduction exposes pivots and solutions, solving linear systems mechanically every time. 2. So the answer stands: Row reduction exposes pivots and solutions, solving linear systems mechanically every time.
linear_algebra
P = 1/8.
null
mat_0100
worked_example
en
A fair 8-sided die is rolled. Show P(one specific number).
[ "Favourable: 1.", "Possible: 8.", "P = 1/8." ]
math
Answer: P = 1/8. Steps: 1. Favourable: 1. 2. Possible: 8. 3. P = 1/8.
probability
Zbytek: 1.
null
mat_0101
worked_example
cs
Spočítej (50) mod 7.
[ "Děl 50 sedmi.", "7×7 = 49.", "50 − 49 = 1." ]
math
Answer: Zbytek: 1. Steps: 1. Děl 50 sedmi. 2. 7×7 = 49. 3. 50 − 49 = 1.
number_theory
C(4,2) je 6.
{ "A": "6", "B": "2", "C": "10", "D": "14" }
mat_0102
multiple_choice
cs
Vypočítej kombinační číslo C(4,2).
[ "4×3/2.", "= 6.", "Vyber možnost A." ]
math
Answer: 6 Steps: 1. 4×3/2. 2. = 6. 3. Vyber možnost A. Answer: (A)
combinatorics
Rows: 16.
null
mat_0103
worked_example
en
A proof checks all cases of 4 boolean variables. How many rows?
[ "2 choices each.", "2^4 = 16." ]
math
Answer: Rows: 16. Steps: 1. 2 choices each. 2. 2^4 = 16.
proofs
Limita je hodnota, k níž se funkce blíží, i když v bodě není definována.
null
mat_0104
concept
cs
Co je limita?
[ "Limita je hodnota, k níž se funkce blíží, i když v bodě není definována.", "Odpověď tedy platí: Limita je hodnota, k níž se funkce blíží, i když v bodě není definována." ]
math
Answer: Limita je hodnota, k níž se funkce blíží, i když v bodě není definována. Steps: 1. Limita je hodnota, k níž se funkce blíží, i když v bodě není definována. 2. Odpověď tedy platí: Limita je hodnota, k níž se funkce blíží, i když v bodě není definována.
calculus
Dot product: 19.
null
mat_0105
worked_example
en
Compute (3,2) · (3,5) step by step.
[ "Multiply components.", "3×3 + 2×5.", "= 19." ]
math
Answer: Dot product: 19. Steps: 1. Multiply components. 2. 3×3 + 2×5. 3. = 19.
linear_algebra
E = 4.
null
mat_0106
worked_example
en
Compute E of a uniform draw from {1..7}.
[ "Mean of 1..7.", "(7+1)/2.", "E = 4." ]
math
Answer: E = 4. Steps: 1. Mean of 1..7. 2. (7+1)/2. 3. E = 4.
probability
The answer is Chinese remainder.
{ "A": "Chinese remainder", "B": "Blind luck", "C": "Wild guess", "D": "Long nap" }
mat_0107
multiple_choice
en
Choose: what merges congruences?
[ "One solution modulo product.", "So: Chinese remainder.", "Select option A." ]
math
Answer: Chinese remainder Steps: 1. One solution modulo product. 2. So: Chinese remainder. 3. Select option A. Answer: (A)
number_theory
It builds nCr rows by addition, revealing symmetry and binomial patterns visually.
null
mat_0108
concept
en
Why Pascal's triangle?
[ "It builds nCr rows by addition, revealing symmetry and binomial patterns visually.", "So the answer stands: It builds nCr rows by addition, revealing symmetry and binomial patterns visually." ]
math
Answer: It builds nCr rows by addition, revealing symmetry and binomial patterns visually. Steps: 1. It builds nCr rows by addition, revealing symmetry and binomial patterns visually. 2. So the answer stands: It builds nCr rows by addition, revealing symmetry and binomial patterns visually.
combinatorics
Sum: 36.
null
mat_0109
worked_example
en
Prove by formula: find the sum 1 + 2 + ... + 8.
[ "Pair 1+8, 2+7, ...", "Use 8×9/2.", "= 36." ]
math
Answer: Sum: 36. Steps: 1. Pair 1+8, 2+7, ... 2. Use 8×9/2. 3. = 36.
proofs
Limit: 10.
null
mat_0110
worked_example
en
Evaluate the limit of (x² − 5²)/(x − 5) as x → 5.
[ "Factor: (x−5)(x+5).", "Cancel (x−5).", "Plug 5: 5+5 = 10." ]
math
Answer: Limit: 10. Steps: 1. Factor: (x−5)(x+5). 2. Cancel (x−5). 3. Plug 5: 5+5 = 10.
calculus
Determinant: 18.
null
mat_0111
worked_example
en
Compute det [[4,1],[2,5]] step by step.
[ "ad − bc.", "4×5 − 1×2.", "= 18." ]
math
Answer: Determinant: 18. Steps: 1. ad − bc. 2. 4×5 − 1×2. 3. = 18.
linear_algebra
Pravděpodobnost měří šanci od 0 do 1 a axiomy zaručují soudržné uvažování.
null
mat_0112
concept
cs
Co je pravděpodobnost?
[ "Pravděpodobnost měří šanci od 0 do 1 a axiomy zaručují soudržné uvažování.", "Odpověď tedy platí: Pravděpodobnost měří šanci od 0 do 1 a axiomy zaručují soudržné uvažování." ]
math
Answer: Pravděpodobnost měří šanci od 0 do 1 a axiomy zaručují soudržné uvažování. Steps: 1. Pravděpodobnost měří šanci od 0 do 1 a axiomy zaručují soudržné uvažování. 2. Odpověď tedy platí: Pravděpodobnost měří šanci od 0 do 1 a axiomy zaručují soudržné uvažování.
probability
The gcd is 9.
{ "A": "6", "B": "9", "C": "12", "D": "15" }
mat_0113
multiple_choice
en
Find gcd(18, 27).
[ "Factor 3 out twice.", "gcd = 9.", "Select option B." ]
math
Answer: 9 Steps: 1. Factor 3 out twice. 2. gcd = 9. 3. Select option B. Answer: (B)
number_theory
C(8,2) = 28.
null
mat_0114
worked_example
en
Show the computation of C(8,2).
[ "Formula n(n−1)/2.", "8×7/2.", "= 28." ]
math
Answer: C(8,2) = 28. Steps: 1. Formula n(n−1)/2. 2. 8×7/2. 3. = 28.
combinatorics
The answer is Witness or counting.
{ "A": "Witness or counting", "B": "Long names", "C": "Big fonts", "D": "Hope alone" }
mat_0115
multiple_choice
en
Choose: what proves existence?
[ "Build or count it.", "So: Witness or counting.", "Select option A." ]
math
Answer: Witness or counting Steps: 1. Build or count it. 2. So: Witness or counting. 3. Select option A. Answer: (A)
proofs
Differentiation finds maxima, minima, and speeds, turning change questions into algebra.
null
mat_0116
concept
en
Why differentiate?
[ "Differentiation finds maxima, minima, and speeds, turning change questions into algebra.", "So the answer stands: Differentiation finds maxima, minima, and speeds, turning change questions into algebra." ]
math
Answer: Differentiation finds maxima, minima, and speeds, turning change questions into algebra. Steps: 1. Differentiation finds maxima, minima, and speeds, turning change questions into algebra. 2. So the answer stands: Differentiation finds maxima, minima, and speeds, turning change questions into algebra.
calculus
Trace: 11.
null
mat_0117
worked_example
en
Compute the trace of [[5,0],[0,6]].
[ "Sum diagonal.", "5 + 6.", "= 11." ]
math
Answer: Trace: 11. Steps: 1. Sum diagonal. 2. 5 + 6. 3. = 11.
linear_algebra
Pravděpodobnost je 1/6.
{ "A": "1/6", "B": "1/5", "C": "1/7", "D": "2/6" }
mat_0118
multiple_choice
cs
Hází se férovou 6-stěnnou kostkou. Jaká je pravděpodobnost jednoho konkrétního čísla?
[ "1 stěna z 6.", "P = 1/6.", "Vyber možnost A." ]
math
Answer: 1/6 Steps: 1. 1 stěna z 6. 2. P = 1/6. 3. Vyber možnost A. Answer: (A)
probability
NSN = 40.
null
mat_0119
worked_example
cs
Spočítej NSN(5, 8) krok za krokem.
[ "NSD(5,8) = 1.", "5×8/1.", "= 40." ]
math
Answer: NSN = 40. Steps: 1. NSD(5,8) = 1. 2. 5×8/1. 3. = 40.
number_theory
The answer is Recurrence.
{ "A": "Recurrence", "B": "Prophecy", "C": "Rumour", "D": "Dream" }
mat_0120
multiple_choice
en
Choose: what defines from the past?
[ "Base plus step.", "So: Recurrence.", "Select option A." ]
math
Answer: Recurrence Steps: 1. Base plus step. 2. So: Recurrence. 3. Select option A. Answer: (A)
combinatorics
Half: 10, so 20 is even.
null
mat_0121
worked_example
en
Show N² + N is even for N = 4 by computing its half.
[ "4² + 4 = 20.", "20 / 2 = 10.", "Integer, so even." ]
math
Answer: Half: 10, so 20 is even. Steps: 1. 4² + 4 = 20. 2. 20 / 2 = 10. 3. Integer, so even.
proofs
The chain rule differentiates compositions by multiplying outer and inner derivatives together.
null
mat_0122
concept
en
What is the chain rule?
[ "The chain rule differentiates compositions by multiplying outer and inner derivatives together.", "So the answer stands: The chain rule differentiates compositions by multiplying outer and inner derivatives together." ]
math
Answer: The chain rule differentiates compositions by multiplying outer and inner derivatives together. Steps: 1. The chain rule differentiates compositions by multiplying outer and inner derivatives together. 2. So the answer stands: The chain rule differentiates compositions by multiplying outer and inner derivatives...
calculus
An inverse matrix undoes the original map, existing exactly when the determinant is nonzero.
null
mat_0123
concept
en
What is an inverse?
[ "An inverse matrix undoes the original map, existing exactly when the determinant is nonzero.", "So the answer stands: An inverse matrix undoes the original map, existing exactly when the determinant is nonzero." ]
math
Answer: An inverse matrix undoes the original map, existing exactly when the determinant is nonzero. Steps: 1. An inverse matrix undoes the original map, existing exactly when the determinant is nonzero. 2. So the answer stands: An inverse matrix undoes the original map, existing exactly when the determinant is nonzero...
linear_algebra
It returns spread to original units, making variability interpretable in context.
null
mat_0124
concept
en
Why standard deviation?
[ "It returns spread to original units, making variability interpretable in context.", "So the answer stands: It returns spread to original units, making variability interpretable in context." ]
math
Answer: It returns spread to original units, making variability interpretable in context. Steps: 1. It returns spread to original units, making variability interpretable in context. 2. So the answer stands: It returns spread to original units, making variability interpretable in context.
probability
The least common multiple is the smallest positive integer both numbers divide.
null
mat_0125
concept
en
What is the lcm?
[ "The least common multiple is the smallest positive integer both numbers divide.", "So the answer stands: The least common multiple is the smallest positive integer both numbers divide." ]
math
Answer: The least common multiple is the smallest positive integer both numbers divide. Steps: 1. The least common multiple is the smallest positive integer both numbers divide. 2. So the answer stands: The least common multiple is the smallest positive integer both numbers divide.
number_theory
P(7,3) = 210.
null
mat_0126
worked_example
en
Show the computation of P(7,3).
[ "n(n−1)(n−2).", "7×6×5.", "= 210." ]
math
Answer: P(7,3) = 210. Steps: 1. n(n−1)(n−2). 2. 7×6×5. 3. = 210.
combinatorics
Rows: 32.
null
mat_0127
worked_example
en
A proof checks all cases of 5 boolean variables. How many rows?
[ "2 choices each.", "2^5 = 32." ]
math
Answer: Rows: 32. Steps: 1. 2 choices each. 2. 2^5 = 32.
proofs
The product rule splits (fg)' into f'g + fg', handling products no single rule covers.
null
mat_0128
concept
en
Why learn the product rule?
[ "The product rule splits (fg)' into f'g + fg', handling products no single rule covers.", "So the answer stands: The product rule splits (fg)' into f'g + fg', handling products no single rule covers." ]
math
Answer: The product rule splits (fg)' into f'g + fg', handling products no single rule covers. Steps: 1. The product rule splits (fg)' into f'g + fg', handling products no single rule covers. 2. So the answer stands: The product rule splits (fg)' into f'g + fg', handling products no single rule covers.
calculus
Eigenvalues reveal stretch directions of a map, unlocking stability and long-term behaviour.
null
mat_0129
concept
en
Why study eigenvalues?
[ "Eigenvalues reveal stretch directions of a map, unlocking stability and long-term behaviour.", "So the answer stands: Eigenvalues reveal stretch directions of a map, unlocking stability and long-term behaviour." ]
math
Answer: Eigenvalues reveal stretch directions of a map, unlocking stability and long-term behaviour. Steps: 1. Eigenvalues reveal stretch directions of a map, unlocking stability and long-term behaviour. 2. So the answer stands: Eigenvalues reveal stretch directions of a map, unlocking stability and long-term behaviour...
linear_algebra
P(red) = 5/9.
null
mat_0130
worked_example
en
A bag holds 5 red and 4 blue marbles. Show P(red).
[ "Red: 5.", "Total: 9.", "P = 5/9." ]
math
Answer: P(red) = 5/9. Steps: 1. Red: 5. 2. Total: 9. 3. P = 5/9.
probability
The remainder is 8.
{ "A": "0", "B": "1", "C": "8", "D": "2" }
mat_0131
multiple_choice
en
Find (107) mod 9.
[ "107 ÷ 9.", "Remainder 8.", "Select option C." ]
math
Answer: 8 Steps: 1. 107 ÷ 9. 2. Remainder 8. 3. Select option C. Answer: (C)
number_theory
It expands (a+b)^n into nCr-weighted terms, linking algebra to counting.
null
mat_0132
concept
en
What is the binomial theorem?
[ "It expands (a+b)^n into nCr-weighted terms, linking algebra to counting.", "So the answer stands: It expands (a+b)^n into nCr-weighted terms, linking algebra to counting." ]
math
Answer: It expands (a+b)^n into nCr-weighted terms, linking algebra to counting. Steps: 1. It expands (a+b)^n into nCr-weighted terms, linking algebra to counting. 2. So the answer stands: It expands (a+b)^n into nCr-weighted terms, linking algebra to counting.
combinatorics
The table has 8 rows.
{ "A": "6", "B": "8", "C": "10", "D": "12" }
mat_0133
multiple_choice
en
How many rows does a truth table with 3 variables have?
[ "2^3 rows.", "Total: 8.", "Select option B." ]
math
Answer: 8 Steps: 1. 2^3 rows. 2. Total: 8. 3. Select option B. Answer: (B)
proofs
Spojité funkce nemají skoky, malé změny vstupu dávají malé změny výstupu.
null
mat_0134
concept
cs
Proč spojitost?
[ "Spojité funkce nemají skoky, malé změny vstupu dávají malé změny výstupu.", "Odpověď tedy platí: Spojité funkce nemají skoky, malé změny vstupu dávají malé změny výstupu." ]
math
Answer: Spojité funkce nemají skoky, malé změny vstupu dávají malé změny výstupu. Steps: 1. Spojité funkce nemají skoky, malé změny vstupu dávají malé změny výstupu. 2. Odpověď tedy platí: Spojité funkce nemají skoky, malé změny vstupu dávají malé změny výstupu.
calculus
Dot product: 27.
null
mat_0135
worked_example
en
Compute (4,3) · (3,5) step by step.
[ "Multiply components.", "4×3 + 3×5.", "= 27." ]
math
Answer: Dot product: 27. Steps: 1. Multiply components. 2. 4×3 + 3×5. 3. = 27.
linear_algebra
P = 1/9.
null
mat_0136
worked_example
en
A fair 9-sided die is rolled. Show P(one specific number).
[ "Favourable: 1.", "Possible: 9.", "P = 1/9." ]
math
Answer: P = 1/9. Steps: 1. Favourable: 1. 2. Possible: 9. 3. P = 1/9.
probability
The lcm is 30.
{ "A": "28", "B": "32", "C": "34", "D": "30" }
mat_0137
multiple_choice
en
Find lcm(5, 6).
[ "5×6/gcd.", "lcm = 30.", "Select option D." ]
math
Answer: 30 Steps: 1. 5×6/gcd. 2. lcm = 30. 3. Select option D. Answer: (D)
number_theory
C(5,2) = 10.
null
mat_0138
worked_example
cs
Ukaž výpočet C(5,2).
[ "Vzorec n(n−1)/2.", "5×4/2.", "= 10." ]
math
Answer: C(5,2) = 10. Steps: 1. Vzorec n(n−1)/2. 2. 5×4/2. 3. = 10.
combinatorics
Sum: 45.
null
mat_0139
worked_example
en
Prove by formula: find the sum 1 + 2 + ... + 9.
[ "Pair 1+9, 2+8, ...", "Use 9×10/2.", "= 45." ]
math
Answer: Sum: 45. Steps: 1. Pair 1+9, 2+8, ... 2. Use 9×10/2. 3. = 45.
proofs
Derivace je okamžitá rychlost změny, směrnice tečny v každém bodě.
null
mat_0140
concept
cs
Co je derivace?
[ "Derivace je okamžitá rychlost změny, směrnice tečny v každém bodě.", "Odpověď tedy platí: Derivace je okamžitá rychlost změny, směrnice tečny v každém bodě." ]
math
Answer: Derivace je okamžitá rychlost změny, směrnice tečny v každém bodě. Steps: 1. Derivace je okamžitá rychlost změny, směrnice tečny v každém bodě. 2. Odpověď tedy platí: Derivace je okamžitá rychlost změny, směrnice tečny v každém bodě.
calculus
Vektor je veličina se směrem a velikostí, sčítá se po složkách.
null
mat_0141
concept
cs
Co je vektor?
[ "Vektor je veličina se směrem a velikostí, sčítá se po složkách.", "Odpověď tedy platí: Vektor je veličina se směrem a velikostí, sčítá se po složkách." ]
math
Answer: Vektor je veličina se směrem a velikostí, sčítá se po složkách. Steps: 1. Vektor je veličina se směrem a velikostí, sčítá se po složkách. 2. Odpověď tedy platí: Vektor je veličina se směrem a velikostí, sčítá se po složkách.
linear_algebra
A random variable maps outcomes to numbers, letting chance be studied with functions.
null
mat_0142
concept
en
What is a random variable?
[ "A random variable maps outcomes to numbers, letting chance be studied with functions.", "So the answer stands: A random variable maps outcomes to numbers, letting chance be studied with functions." ]
math
Answer: A random variable maps outcomes to numbers, letting chance be studied with functions. Steps: 1. A random variable maps outcomes to numbers, letting chance be studied with functions. 2. So the answer stands: A random variable maps outcomes to numbers, letting chance be studied with functions.
probability
lcm = 40.
null
mat_0143
worked_example
en
Compute lcm(5, 8) step by step.
[ "gcd(5,8) = 1.", "5×8/1.", "= 40." ]
math
Answer: lcm = 40. Steps: 1. gcd(5,8) = 1. 2. 5×8/1. 3. = 40.
number_theory
It counts distributions of identical items into boxes via separator placements.
null
mat_0144
concept
en
Why stars and bars?
[ "It counts distributions of identical items into boxes via separator placements.", "So the answer stands: It counts distributions of identical items into boxes via separator placements." ]
math
Answer: It counts distributions of identical items into boxes via separator placements. Steps: 1. It counts distributions of identical items into boxes via separator placements. 2. So the answer stands: It counts distributions of identical items into boxes via separator placements.
combinatorics
The sum is 21.
{ "A": "15", "B": "27", "C": "21", "D": "33" }
mat_0145
multiple_choice
en
What is the sum 1 + 2 + ... + 6?
[ "6×7/2.", "Sum = 21.", "Select option C." ]
math
Answer: 21 Steps: 1. 6×7/2. 2. Sum = 21. 3. Select option C. Answer: (C)
proofs
The answer is Instant rate.
{ "A": "Total area", "B": "Long length", "C": "Big volume", "D": "Instant rate" }
mat_0146
multiple_choice
en
Choose: what does f' measure?
[ "Tangent slope read.", "So: Instant rate.", "Select option D." ]
math
Answer: Instant rate Steps: 1. Tangent slope read. 2. So: Instant rate. 3. Select option D. Answer: (D)
calculus
Determinant: 28.
null
mat_0147
worked_example
en
Compute det [[5,1],[2,6]] step by step.
[ "ad − bc.", "5×6 − 1×2.", "= 28." ]
math
Answer: Determinant: 28. Steps: 1. ad − bc. 2. 5×6 − 1×2. 3. = 28.
linear_algebra
The answer is Sample space.
{ "A": "Wish list", "B": "Guess bag", "C": "Hope chest", "D": "Sample space" }
mat_0148
multiple_choice
en
Choose: what lists all outcomes?
[ "Events are subsets.", "So: Sample space.", "Select option D." ]
math
Answer: Sample space Steps: 1. Events are subsets. 2. So: Sample space. 3. Select option D. Answer: (D)
probability
It writes gcd(a,b) as a combination ax+by, unlocking inverses and Diophantine solving.
null
mat_0149
concept
en
Why Bézout's identity?
[ "It writes gcd(a,b) as a combination ax+by, unlocking inverses and Diophantine solving.", "So the answer stands: It writes gcd(a,b) as a combination ax+by, unlocking inverses and Diophantine solving." ]
math
Answer: It writes gcd(a,b) as a combination ax+by, unlocking inverses and Diophantine solving. Steps: 1. It writes gcd(a,b) as a combination ax+by, unlocking inverses and Diophantine solving. 2. So the answer stands: It writes gcd(a,b) as a combination ax+by, unlocking inverses and Diophantine solving.
number_theory
C(5,2) is 10.
{ "A": "5", "B": "10", "C": "15", "D": "20" }
mat_0150
multiple_choice
en
Compute C(5,2).
[ "5×4/2.", "= 10.", "Select option B." ]
math
Answer: 10 Steps: 1. 5×4/2. 2. = 10. 3. Select option B. Answer: (B)
combinatorics