answer
string
choices
dict
id
string
kind
string
lang
string
question
string
steps
list
subject
string
text
string
topic
string
The lcm is 6.
{ "A": "6", "B": "4", "C": "8", "D": "10" }
mat_0251
multiple_choice
en
Find lcm(6, 6).
[ "6×6/gcd.", "lcm = 6.", "Select option A." ]
math
Answer: 6 Steps: 1. 6×6/gcd. 2. lcm = 6. 3. Select option A. Answer: (A)
number_theory
C(10,3) = 120.
null
mat_0252
worked_example
en
Show the computation of C(10,3).
[ "n(n−1)(n−2)/6.", "10×9×8/6.", "= 120." ]
math
Answer: C(10,3) = 120. Steps: 1. n(n−1)(n−2)/6. 2. 10×9×8/6. 3. = 120.
combinatorics
Half: 21, so 42 is even.
null
mat_0253
worked_example
en
Show N² + N is even for N = 6 by computing its half.
[ "6² + 6 = 42.", "42 / 2 = 21.", "Integer, so even." ]
math
Answer: Half: 21, so 42 is even. Steps: 1. 6² + 6 = 42. 2. 42 / 2 = 21. 3. Integer, so even.
proofs
Limita: 6.
null
mat_0254
worked_example
cs
Vyčísli limitu (x² − 3²)/(x − 3) pro x → 3.
[ "Rozlož: (x−3)(x+3).", "Pokrať (x−3).", "Dosaď 3: 3+3 = 6." ]
math
Answer: Limita: 6. Steps: 1. Rozlož: (x−3)(x+3). 2. Pokrať (x−3). 3. Dosaď 3: 3+3 = 6.
calculus
The determinant is 12.
{ "A": "9", "B": "15", "C": "12", "D": "18" }
mat_0255
multiple_choice
en
Find the determinant of [[3,2],[3,6]].
[ "3×6 − 2×3.", "Det = 12.", "Select option C." ]
math
Answer: 12 Steps: 1. 3×6 − 2×3. 2. Det = 12. 3. Select option C. Answer: (C)
linear_algebra
Bayes obrací podmíněnosti a usuzuje příčiny z následků.
null
mat_0256
concept
cs
Proč Bayesova věta?
[ "Bayes obrací podmíněnosti a usuzuje příčiny z následků.", "Odpověď tedy platí: Bayes obrací podmíněnosti a usuzuje příčiny z následků." ]
math
Answer: Bayes obrací podmíněnosti a usuzuje příčiny z následků. Steps: 1. Bayes obrací podmíněnosti a usuzuje příčiny z následků. 2. Odpověď tedy platí: Bayes obrací podmíněnosti a usuzuje příčiny z následků.
probability
NSN je 12.
{ "A": "10", "B": "14", "C": "12", "D": "16" }
mat_0257
multiple_choice
cs
Najdi nejmenší společný násobek NSN(4, 6).
[ "4×6/NSD.", "NSN = 12.", "Vyber možnost C." ]
math
Answer: 12 Steps: 1. 4×6/NSD. 2. NSN = 12. 3. Vyber možnost C. Answer: (C)
number_theory
C(10,2) = 45.
null
mat_0258
worked_example
en
Show the computation of C(10,2).
[ "Formula n(n−1)/2.", "10×9/2.", "= 45." ]
math
Answer: C(10,2) = 45. Steps: 1. Formula n(n−1)/2. 2. 10×9/2. 3. = 45.
combinatorics
Součet: 28.
null
mat_0259
worked_example
cs
Dokaž vzorcem: najdi součet 1 + 2 + ... + 7.
[ "Páruj 1+7, 2+6, ...", "Použij 7×8/2.", "= 28." ]
math
Answer: Součet: 28. Steps: 1. Páruj 1+7, 2+6, ... 2. Použij 7×8/2. 3. = 28.
proofs
Integration recovers totals from rates, computing areas, volumes, and accumulated change.
null
mat_0260
concept
en
Why integrate?
[ "Integration recovers totals from rates, computing areas, volumes, and accumulated change.", "So the answer stands: Integration recovers totals from rates, computing areas, volumes, and accumulated change." ]
math
Answer: Integration recovers totals from rates, computing areas, volumes, and accumulated change. Steps: 1. Integration recovers totals from rates, computing areas, volumes, and accumulated change. 2. So the answer stands: Integration recovers totals from rates, computing areas, volumes, and accumulated change.
calculus
Trace: 15.
null
mat_0261
worked_example
en
Compute the trace of [[7,0],[0,8]].
[ "Sum diagonal.", "7 + 8.", "= 15." ]
math
Answer: Trace: 15. Steps: 1. Sum diagonal. 2. 7 + 8. 3. = 15.
linear_algebra
The probability is 1/8.
{ "A": "1/7", "B": "1/9", "C": "1/8", "D": "2/8" }
mat_0262
multiple_choice
en
A fair 8-sided die is rolled. What is the probability of one specific number?
[ "1 face of 8.", "P = 1/8.", "Select option C." ]
math
Answer: 1/8 Steps: 1. 1 face of 8. 2. P = 1/8. 3. Select option C. Answer: (C)
probability
NSN = 24.
null
mat_0263
worked_example
cs
Spočítej NSN(6, 8) krok za krokem.
[ "NSD(6,8) = 2.", "6×8/2.", "= 24." ]
math
Answer: NSN = 24. Steps: 1. NSD(6,8) = 2. 2. 6×8/2. 3. = 24.
number_theory
Derangements count fixed-point-free orders, modelling secret Santas and mismatches.
null
mat_0264
concept
en
Why derangements?
[ "Derangements count fixed-point-free orders, modelling secret Santas and mismatches.", "So the answer stands: Derangements count fixed-point-free orders, modelling secret Santas and mismatches." ]
math
Answer: Derangements count fixed-point-free orders, modelling secret Santas and mismatches. Steps: 1. Derangements count fixed-point-free orders, modelling secret Santas and mismatches. 2. So the answer stands: Derangements count fixed-point-free orders, modelling secret Santas and mismatches.
combinatorics
The sum is 28.
{ "A": "21", "B": "35", "C": "42", "D": "28" }
mat_0265
multiple_choice
en
What is the sum 1 + 2 + ... + 7?
[ "7×8/2.", "Sum = 28.", "Select option D." ]
math
Answer: 28 Steps: 1. 7×8/2. 2. Sum = 28. 3. Select option D. Answer: (D)
proofs
Integral: 512.
null
mat_0266
worked_example
en
Evaluate the integral of 3x² from 0 to 8.
[ "Antiderivative: x³.", "Evaluate 0 to 8.", "8³ − 0 = 512." ]
math
Answer: Integral: 512. Steps: 1. Antiderivative: x³. 2. Evaluate 0 to 8. 3. 8³ − 0 = 512.
calculus
The trace is 11.
{ "A": "9", "B": "13", "C": "15", "D": "11" }
mat_0267
multiple_choice
en
Find the trace of [[4,1],[2,7]].
[ "4 + 7.", "Trace = 11.", "Select option D." ]
math
Answer: 11 Steps: 1. 4 + 7. 2. Trace = 11. 3. Select option D. Answer: (D)
linear_algebra
P = 1/6.
null
mat_0268
worked_example
cs
Hází se férovou 6-stěnnou kostkou. Ukaž P(jedno konkrétní číslo).
[ "Příznivé: 1.", "Možné: 6.", "P = 1/6." ]
math
Answer: P = 1/6. Steps: 1. Příznivé: 1. 2. Možné: 6. 3. P = 1/6.
probability
Každé číslo nad 1 se jednoznačně rozkládá na prvočísla.
null
mat_0269
concept
cs
Co je základní věta aritmetiky?
[ "Každé číslo nad 1 se jednoznačně rozkládá na prvočísla.", "Odpověď tedy platí: Každé číslo nad 1 se jednoznačně rozkládá na prvočísla." ]
math
Answer: Každé číslo nad 1 se jednoznačně rozkládá na prvočísla. Steps: 1. Každé číslo nad 1 se jednoznačně rozkládá na prvočísla. 2. Odpověď tedy platí: Každé číslo nad 1 se jednoznačně rozkládá na prvočísla.
number_theory
C(6,2) is 15.
{ "A": "9", "B": "21", "C": "15", "D": "27" }
mat_0270
multiple_choice
en
Compute C(6,2).
[ "6×5/2.", "= 15.", "Select option C." ]
math
Answer: 15 Steps: 1. 6×5/2. 2. = 15. 3. Select option C. Answer: (C)
combinatorics
The value is 30.
{ "A": "30", "B": "28", "C": "32", "D": "34" }
mat_0271
multiple_choice
en
Compute N² + N for N = 5.
[ "5² + 5.", "Value = 30.", "Select option A." ]
math
Answer: 30 Steps: 1. 5² + 5. 2. Value = 30. 3. Select option A. Answer: (A)
proofs
It links derivatives and integrals, so definite integrals equal antiderivative differences.
null
mat_0272
concept
en
What is the fundamental theorem of calculus?
[ "It links derivatives and integrals, so definite integrals equal antiderivative differences.", "So the answer stands: It links derivatives and integrals, so definite integrals equal antiderivative differences." ]
math
Answer: It links derivatives and integrals, so definite integrals equal antiderivative differences. Steps: 1. It links derivatives and integrals, so definite integrals equal antiderivative differences. 2. So the answer stands: It links derivatives and integrals, so definite integrals equal antiderivative differences.
calculus
Dot product: 43.
null
mat_0273
worked_example
en
Compute (6,5) · (3,5) step by step.
[ "Multiply components.", "6×3 + 5×5.", "= 43." ]
math
Answer: Dot product: 43. Steps: 1. Multiply components. 2. 6×3 + 5×5. 3. = 43.
linear_algebra
Nezávislé jevy násobí pravděpodobnosti, výsledek jednoho neovlivní druhý.
null
mat_0274
concept
cs
Co je nezávislost?
[ "Nezávislé jevy násobí pravděpodobnosti, výsledek jednoho neovlivní druhý.", "Odpověď tedy platí: Nezávislé jevy násobí pravděpodobnosti, výsledek jednoho neovlivní druhý." ]
math
Answer: Nezávislé jevy násobí pravděpodobnosti, výsledek jednoho neovlivní druhý. Steps: 1. Nezávislé jevy násobí pravděpodobnosti, výsledek jednoho neovlivní druhý. 2. Odpověď tedy platí: Nezávislé jevy násobí pravděpodobnosti, výsledek jednoho neovlivní druhý.
probability
Remainder: 6.
null
mat_0275
worked_example
en
Compute (83) mod 7.
[ "Divide 83 by 7.", "7×11 = 77.", "83 − 77 = 6." ]
math
Answer: Remainder: 6. Steps: 1. Divide 83 by 7. 2. 7×11 = 77. 3. 83 − 77 = 6.
number_theory
P(5,2) is 20.
{ "A": "15", "B": "25", "C": "30", "D": "20" }
mat_0276
multiple_choice
en
Compute P(5,2).
[ "5×4.", "= 20.", "Select option D." ]
math
Answer: 20 Steps: 1. 5×4. 2. = 20. 3. Select option D. Answer: (D)
combinatorics
Rows: 128.
null
mat_0277
worked_example
en
A proof checks all cases of 7 boolean variables. How many rows?
[ "2 choices each.", "2^7 = 128." ]
math
Answer: Rows: 128. Steps: 1. 2 choices each. 2. 2^7 = 128.
proofs
Substitution rewrites messy integrals in simpler variables, undoing the chain rule.
null
mat_0278
concept
en
Why substitute in integrals?
[ "Substitution rewrites messy integrals in simpler variables, undoing the chain rule.", "So the answer stands: Substitution rewrites messy integrals in simpler variables, undoing the chain rule." ]
math
Answer: Substitution rewrites messy integrals in simpler variables, undoing the chain rule. Steps: 1. Substitution rewrites messy integrals in simpler variables, undoing the chain rule. 2. So the answer stands: Substitution rewrites messy integrals in simpler variables, undoing the chain rule.
calculus
Determinant: 54.
null
mat_0279
worked_example
en
Compute det [[7,1],[2,8]] step by step.
[ "ad − bc.", "7×8 − 1×2.", "= 54." ]
math
Answer: Determinant: 54. Steps: 1. ad − bc. 2. 7×8 − 1×2. 3. = 54.
linear_algebra
P(red) = 7/11.
null
mat_0280
worked_example
en
A bag holds 7 red and 4 blue marbles. Show P(red).
[ "Red: 7.", "Total: 11.", "P = 7/11." ]
math
Answer: P(red) = 7/11. Steps: 1. Red: 7. 2. Total: 11. 3. P = 7/11.
probability
lcm = 8.
null
mat_0281
worked_example
en
Compute lcm(8, 8) step by step.
[ "gcd(8,8) = 8.", "8×8/8.", "= 8." ]
math
Answer: lcm = 8. Steps: 1. gcd(8,8) = 8. 2. 8×8/8. 3. = 8.
number_theory
A combination selects without order, counted by nCr for r from n.
null
mat_0282
concept
en
What is a combination?
[ "A combination selects without order, counted by nCr for r from n.", "So the answer stands: A combination selects without order, counted by nCr for r from n." ]
math
Answer: A combination selects without order, counted by nCr for r from n. Steps: 1. A combination selects without order, counted by nCr for r from n. 2. So the answer stands: A combination selects without order, counted by nCr for r from n.
combinatorics
The answer is Claim is false.
{ "A": "Claim is true", "B": "Claim is false", "C": "Nothing at all", "D": "Two claims" }
mat_0283
multiple_choice
en
Choose: what does contradiction assume?
[ "Absurdity follows.", "So: Claim is false.", "Select option B." ]
math
Answer: Claim is false Steps: 1. Absurdity follows. 2. So: Claim is false. 3. Select option B. Answer: (B)
proofs
It trades one hard integral for an easier one via uv minus the integral of v du.
null
mat_0284
concept
en
What is integration by parts?
[ "It trades one hard integral for an easier one via uv minus the integral of v du.", "So the answer stands: It trades one hard integral for an easier one via uv minus the integral of v du." ]
math
Answer: It trades one hard integral for an easier one via uv minus the integral of v du. Steps: 1. It trades one hard integral for an easier one via uv minus the integral of v du. 2. So the answer stands: It trades one hard integral for an easier one via uv minus the integral of v du.
calculus
Trace: 17.
null
mat_0285
worked_example
en
Compute the trace of [[8,0],[0,9]].
[ "Sum diagonal.", "8 + 9.", "= 17." ]
math
Answer: Trace: 17. Steps: 1. Sum diagonal. 2. 8 + 9. 3. = 17.
linear_algebra
E = 3.
null
mat_0286
worked_example
cs
Spočítej E rovnoměrného tahu z {1..5}.
[ "Průměr 1..5.", "(5+1)/2.", "E = 3." ]
math
Answer: E = 3. Steps: 1. Průměr 1..5. 2. (5+1)/2. 3. E = 3.
probability
For prime p, a^(p-1) is 1 mod p, powering fast primality checks and inverses.
null
mat_0287
concept
en
What is Fermat's little theorem?
[ "For prime p, a^(p-1) is 1 mod p, powering fast primality checks and inverses.", "So the answer stands: For prime p, a^(p-1) is 1 mod p, powering fast primality checks and inverses." ]
math
Answer: For prime p, a^(p-1) is 1 mod p, powering fast primality checks and inverses. Steps: 1. For prime p, a^(p-1) is 1 mod p, powering fast primality checks and inverses. 2. So the answer stands: For prime p, a^(p-1) is 1 mod p, powering fast primality checks and inverses.
number_theory
P(9,3) = 504.
null
mat_0288
worked_example
en
Show the computation of P(9,3).
[ "n(n−1)(n−2).", "9×8×7.", "= 504." ]
math
Answer: P(9,3) = 504. Steps: 1. n(n−1)(n−2). 2. 9×8×7. 3. = 504.
combinatorics
The answer is Helper claim.
{ "A": "Long book", "B": "Final answer", "C": "Helper claim", "D": "New axiom" }
mat_0289
multiple_choice
en
Choose: what is a lemma?
[ "Main proof uses it.", "So: Helper claim.", "Select option C." ]
math
Answer: Helper claim Steps: 1. Main proof uses it. 2. So: Helper claim. 3. Select option C. Answer: (C)
proofs
Limit: 16.
null
mat_0290
worked_example
en
Evaluate the limit of (x² − 8²)/(x − 8) as x → 8.
[ "Factor: (x−8)(x+8).", "Cancel (x−8).", "Plug 8: 8+8 = 16." ]
math
Answer: Limit: 16. Steps: 1. Factor: (x−8)(x+8). 2. Cancel (x−8). 3. Plug 8: 8+8 = 16.
calculus
The dot product is 25.
{ "A": "25", "B": "21", "C": "29", "D": "33" }
mat_0291
multiple_choice
en
Find the dot product (3,4) · (3,4).
[ "3×3 + 4×4.", "Product = 25.", "Select option A." ]
math
Answer: 25 Steps: 1. 3×3 + 4×4. 2. Product = 25. 3. Select option A. Answer: (A)
linear_algebra
P = 1/11.
null
mat_0292
worked_example
en
A fair 11-sided die is rolled. Show P(one specific number).
[ "Favourable: 1.", "Possible: 11.", "P = 1/11." ]
math
Answer: P = 1/11. Steps: 1. Favourable: 1. 2. Possible: 11. 3. P = 1/11.
probability
The answer is Remainders.
{ "A": "Guesses", "B": "Remainders", "C": "Hopes", "D": "Dreams" }
mat_0293
multiple_choice
en
Choose: what shrinks gcd pairs?
[ "Euclid runs fast.", "So: Remainders.", "Select option B." ]
math
Answer: Remainders Steps: 1. Euclid runs fast. 2. So: Remainders. 3. Select option B. Answer: (B)
number_theory
They encode sequences as series coefficients, turning recurrences into algebra.
null
mat_0294
concept
en
Why generating functions?
[ "They encode sequences as series coefficients, turning recurrences into algebra.", "So the answer stands: They encode sequences as series coefficients, turning recurrences into algebra." ]
math
Answer: They encode sequences as series coefficients, turning recurrences into algebra. Steps: 1. They encode sequences as series coefficients, turning recurrences into algebra. 2. So the answer stands: They encode sequences as series coefficients, turning recurrences into algebra.
combinatorics
Sum: 66.
null
mat_0295
worked_example
en
Prove by formula: find the sum 1 + 2 + ... + 11.
[ "Pair 1+11, 2+10, ...", "Use 11×12/2.", "= 66." ]
math
Answer: Sum: 66. Steps: 1. Pair 1+11, 2+10, ... 2. Use 11×12/2. 3. = 66.
proofs
The answer is L'Hôpital's rule.
{ "A": "L'Hôpital's rule", "B": "Guessing", "C": "Ignoring", "D": "Deleting" }
mat_0296
multiple_choice
en
Choose: what resolves 0/0?
[ "Differentiate top, bottom.", "So: L'Hôpital's rule.", "Select option A." ]
math
Answer: L'Hôpital's rule Steps: 1. Differentiate top, bottom. 2. So: L'Hôpital's rule. 3. Select option A. Answer: (A)
calculus
Skládá zobrazení přes skalární součiny řádků a sloupců.
null
mat_0297
concept
cs
Co je násobení matic?
[ "Skládá zobrazení přes skalární součiny řádků a sloupců.", "Odpověď tedy platí: Skládá zobrazení přes skalární součiny řádků a sloupců." ]
math
Answer: Skládá zobrazení přes skalární součiny řádků a sloupců. Steps: 1. Skládá zobrazení přes skalární součiny řádků a sloupců. 2. Odpověď tedy platí: Skládá zobrazení přes skalární součiny řádků a sloupců.
linear_algebra
P(červená) = 3/7.
null
mat_0298
worked_example
cs
Sáček má 3 červených a 4 modré kuličky. Ukaž P(červená).
[ "Červené: 3.", "Celkem: 7.", "P = 3/7." ]
math
Answer: P(červená) = 3/7. Steps: 1. Červené: 3. 2. Celkem: 7. 3. P = 3/7.
probability
It generalizes Fermat via totient, so a^phi(n) is 1 mod n for coprime pairs.
null
mat_0299
concept
en
Why Euler's theorem?
[ "It generalizes Fermat via totient, so a^phi(n) is 1 mod n for coprime pairs.", "So the answer stands: It generalizes Fermat via totient, so a^phi(n) is 1 mod n for coprime pairs." ]
math
Answer: It generalizes Fermat via totient, so a^phi(n) is 1 mod n for coprime pairs. Steps: 1. It generalizes Fermat via totient, so a^phi(n) is 1 mod n for coprime pairs. 2. So the answer stands: It generalizes Fermat via totient, so a^phi(n) is 1 mod n for coprime pairs.
number_theory
C(11,3) = 165.
null
mat_0300
worked_example
en
Show the computation of C(11,3).
[ "n(n−1)(n−2)/6.", "11×10×9/6.", "= 165." ]
math
Answer: C(11,3) = 165. Steps: 1. n(n−1)(n−2)/6. 2. 11×10×9/6. 3. = 165.
combinatorics
An existence proof shows some object has a property, either by building one or by counting arguments.
null
mat_0301
concept
en
What is an existence proof?
[ "An existence proof shows some object has a property, either by building one or by counting arguments.", "So the answer stands: An existence proof shows some object has a property, either by building one or by counting arguments." ]
math
Answer: An existence proof shows some object has a property, either by building one or by counting arguments. Steps: 1. An existence proof shows some object has a property, either by building one or by counting arguments. 2. So the answer stands: An existence proof shows some object has a property, either by building o...
proofs
Series sum infinite terms, and convergence tests tell whether the total is finite.
null
mat_0302
concept
en
Why study series?
[ "Series sum infinite terms, and convergence tests tell whether the total is finite.", "So the answer stands: Series sum infinite terms, and convergence tests tell whether the total is finite." ]
math
Answer: Series sum infinite terms, and convergence tests tell whether the total is finite. Steps: 1. Series sum infinite terms, and convergence tests tell whether the total is finite. 2. So the answer stands: Series sum infinite terms, and convergence tests tell whether the total is finite.
calculus
A subspace is a subset closed under the operations, inheriting the vector-space structure.
null
mat_0303
concept
en
What is a subspace?
[ "A subspace is a subset closed under the operations, inheriting the vector-space structure.", "So the answer stands: A subspace is a subset closed under the operations, inheriting the vector-space structure." ]
math
Answer: A subspace is a subset closed under the operations, inheriting the vector-space structure. Steps: 1. A subspace is a subset closed under the operations, inheriting the vector-space structure. 2. So the answer stands: A subspace is a subset closed under the operations, inheriting the vector-space structure.
linear_algebra
It says standardized sums approach normal, explaining the bell curve everywhere.
null
mat_0304
concept
en
Why central limit theorem?
[ "It says standardized sums approach normal, explaining the bell curve everywhere.", "So the answer stands: It says standardized sums approach normal, explaining the bell curve everywhere." ]
math
Answer: It says standardized sums approach normal, explaining the bell curve everywhere. Steps: 1. It says standardized sums approach normal, explaining the bell curve everywhere. 2. So the answer stands: It says standardized sums approach normal, explaining the bell curve everywhere.
probability
gcd = 12.
null
mat_0305
worked_example
en
Compute gcd(24, 36) step by step.
[ "Factor: 24=4×6, 36=6×6.", "Common: 6×gcd(4,6).", "= 6×2 = 12." ]
math
Answer: gcd = 12. Steps: 1. Factor: 24=4×6, 36=6×6. 2. Common: 6×gcd(4,6). 3. = 6×2 = 12.
number_theory
C(7,3) is 35.
{ "A": "35", "B": "28", "C": "42", "D": "49" }
mat_0306
multiple_choice
en
Compute C(7,3).
[ "7×6×5/6.", "= 35.", "Select option A." ]
math
Answer: 35 Steps: 1. 7×6×5/6. 2. = 35. 3. Select option A. Answer: (A)
combinatorics
Tvrzení pro všechna a existuje se dokazují různě, kvantifikátor volí strategii.
null
mat_0307
concept
cs
Proč uvádět kvantifikátory?
[ "Tvrzení pro všechna a existuje se dokazují různě, kvantifikátor volí strategii.", "Odpověď tedy platí: Tvrzení pro všechna a existuje se dokazují různě, kvantifikátor volí strategii." ]
math
Answer: Tvrzení pro všechna a existuje se dokazují různě, kvantifikátor volí strategii. Steps: 1. Tvrzení pro všechna a existuje se dokazují různě, kvantifikátor volí strategii. 2. Odpověď tedy platí: Tvrzení pro všechna a existuje se dokazují různě, kvantifikátor volí strategii.
proofs
f'(2) = 15.
null
mat_0308
worked_example
en
For f(x) = 2x² + 7x, compute f'(2) step by step.
[ "f'(x) = 4x + 7.", "Plug x = 2.", "4×2 + 7 = 15." ]
math
Answer: f'(2) = 15. Steps: 1. f'(x) = 4x + 7. 2. Plug x = 2. 3. 4×2 + 7 = 15.
calculus
Dot product: 51.
null
mat_0309
worked_example
en
Compute (7,6) · (3,5) step by step.
[ "Multiply components.", "7×3 + 6×5.", "= 51." ]
math
Answer: Dot product: 51. Steps: 1. Multiply components. 2. 7×3 + 6×5. 3. = 51.
linear_algebra
The expected value is 3.5.
{ "A": "4.5", "B": "2.5", "C": "5.5", "D": "3.5" }
mat_0310
multiple_choice
en
Find the expected value of a uniform draw from {1..6}.
[ "(6+1)/2.", "E = 3.5.", "Select option D." ]
math
Answer: 3.5 Steps: 1. (6+1)/2. 2. E = 3.5. 3. Select option D. Answer: (D)
probability
Euklides vynásobí známá a přičte jedna, vynutí nový prvočinitel.
null
mat_0311
concept
cs
Proč nekonečně prvočísel?
[ "Euklides vynásobí známá a přičte jedna, vynutí nový prvočinitel.", "Odpověď tedy platí: Euklides vynásobí známá a přičte jedna, vynutí nový prvočinitel." ]
math
Answer: Euklides vynásobí známá a přičte jedna, vynutí nový prvočinitel. Steps: 1. Euklides vynásobí známá a přičte jedna, vynutí nový prvočinitel. 2. Odpověď tedy platí: Euklides vynásobí známá a přičte jedna, vynutí nový prvočinitel.
number_theory
Odpověď je faktoriál.
{ "A": "součet", "B": "průměr", "C": "hádání", "D": "faktoriál" }
mat_0312
multiple_choice
cs
Vyber: co počítá pořadí?
[ "Volby na pozici ubývají.", "Tedy: faktoriál.", "Vyber možnost D." ]
math
Answer: faktoriál Steps: 1. Volby na pozici ubývají. 2. Tedy: faktoriál. 3. Vyber možnost D. Answer: (D)
combinatorics
Half: 28, so 56 is even.
null
mat_0313
worked_example
en
Show N² + N is even for N = 7 by computing its half.
[ "7² + 7 = 56.", "56 / 2 = 28.", "Integer, so even." ]
math
Answer: Half: 28, so 56 is even. Steps: 1. 7² + 7 = 56. 2. 56 / 2 = 28. 3. Integer, so even.
proofs
Limita je 4.
{ "A": "2", "B": "6", "C": "4", "D": "8" }
mat_0314
multiple_choice
cs
Vypočítej limitu (x² − 2²)/(x − 2) pro x → 2.
[ "Rozlož (x−2)(x+2).", "Pokrať, dostaneš 2×2 = 4.", "Vyber možnost C." ]
math
Answer: 4 Steps: 1. Rozlož (x−2)(x+2). 2. Pokrať, dostaneš 2×2 = 4. 3. Vyber možnost C. Answer: (C)
calculus
Determinant je -2.
{ "A": "-2", "B": "-5", "C": "1", "D": "4" }
mat_0315
multiple_choice
cs
Vypočítej determinant matice [[1,2],[3,4]].
[ "1×4 − 2×3.", "Det = -2.", "Vyber možnost A." ]
math
Answer: -2 Steps: 1. 1×4 − 2×3. 2. Det = -2. 3. Vyber možnost A. Answer: (A)
linear_algebra
E = 5.5.
null
mat_0316
worked_example
en
Compute E of a uniform draw from {1..10}.
[ "Mean of 1..10.", "(10+1)/2.", "E = 5.5." ]
math
Answer: E = 5.5. Steps: 1. Mean of 1..10. 2. (10+1)/2. 3. E = 5.5.
probability
NSD = 8.
null
mat_0317
worked_example
cs
Spočítej NSD(16, 24) krok za krokem.
[ "Rozlož: 16=4×4, 24=6×4.", "Společné: 4×NSD(4,6).", "= 4×2 = 8." ]
math
Answer: NSD = 8. Steps: 1. Rozlož: 16=4×4, 24=6×4. 2. Společné: 4×NSD(4,6). 3. = 4×2 = 8.
number_theory
C(6,2) = 15.
null
mat_0318
worked_example
cs
Ukaž výpočet C(6,2).
[ "Vzorec n(n−1)/2.", "6×5/2.", "= 15." ]
math
Answer: C(6,2) = 15. Steps: 1. Vzorec n(n−1)/2. 2. 6×5/2. 3. = 15.
combinatorics
Polovina: 6, číslo 12 je sudé.
null
mat_0319
worked_example
cs
Ukaž, že N² + N je sudé pro N = 3, výpočtem poloviny.
[ "3² + 3 = 12.", "12 / 2 = 6.", "Celé číslo, tedy sudé." ]
math
Answer: Polovina: 6, číslo 12 je sudé. Steps: 1. 3² + 3 = 12. 2. 12 / 2 = 6. 3. Celé číslo, tedy sudé.
proofs
The answer is Endpoints too.
{ "A": "Nowhere else", "B": "Endpoints too", "C": "Only zero", "D": "Far away" }
mat_0320
multiple_choice
en
Choose: where can maxima hide?
[ "Check ends always.", "So: Endpoints too.", "Select option B." ]
math
Answer: Endpoints too Steps: 1. Check ends always. 2. So: Endpoints too. 3. Select option B. Answer: (B)
calculus
Determinant: 70.
null
mat_0321
worked_example
en
Compute det [[8,1],[2,9]] step by step.
[ "ad − bc.", "8×9 − 1×2.", "= 70." ]
math
Answer: Determinant: 70. Steps: 1. ad − bc. 2. 8×9 − 1×2. 3. = 70.
linear_algebra
P(red) is 4/13.
{ "A": "4/13", "B": "9/13", "C": "4/14", "D": "5/13" }
mat_0322
multiple_choice
en
A bag holds 4 red and 9 blue marbles. What is P(red)?
[ "4 of 13.", "P = 4/13.", "Select option A." ]
math
Answer: 4/13 Steps: 1. 4 of 13. 2. P = 4/13. 3. Select option A. Answer: (A)
probability
The answer is Eratosthenes sieve.
{ "A": "Random picks", "B": "Lucky dips", "C": "Eratosthenes sieve", "D": "Slow walks" }
mat_0323
multiple_choice
en
Choose: what lists primes fast?
[ "Multiples crossed out.", "So: Eratosthenes sieve.", "Select option C." ]
math
Answer: Eratosthenes sieve Steps: 1. Multiples crossed out. 2. So: Eratosthenes sieve. 3. Select option C. Answer: (C)
number_theory
A recurrence defines terms from earlier ones, like Fibonacci from its two predecessors.
null
mat_0324
concept
en
What is recurrence?
[ "A recurrence defines terms from earlier ones, like Fibonacci from its two predecessors.", "So the answer stands: A recurrence defines terms from earlier ones, like Fibonacci from its two predecessors." ]
math
Answer: A recurrence defines terms from earlier ones, like Fibonacci from its two predecessors. Steps: 1. A recurrence defines terms from earlier ones, like Fibonacci from its two predecessors. 2. So the answer stands: A recurrence defines terms from earlier ones, like Fibonacci from its two predecessors.
combinatorics
Uniqueness shows at most one object fits, usually by assuming two and deriving they are equal.
null
mat_0325
concept
en
Why prove uniqueness?
[ "Uniqueness shows at most one object fits, usually by assuming two and deriving they are equal.", "So the answer stands: Uniqueness shows at most one object fits, usually by assuming two and deriving they are equal." ]
math
Answer: Uniqueness shows at most one object fits, usually by assuming two and deriving they are equal. Steps: 1. Uniqueness shows at most one object fits, usually by assuming two and deriving they are equal. 2. So the answer stands: Uniqueness shows at most one object fits, usually by assuming two and deriving they are...
proofs
Odpověď je okamžitou rychlost.
{ "A": "celkovou plochu", "B": "dlouhou délku", "C": "velký objem", "D": "okamžitou rychlost" }
mat_0326
multiple_choice
cs
Vyber: co měří f'?
[ "Směrnice tečny čtena.", "Tedy: okamžitou rychlost.", "Vyber možnost D." ]
math
Answer: okamžitou rychlost Steps: 1. Směrnice tečny čtena. 2. Tedy: okamžitou rychlost. 3. Vyber možnost D. Answer: (D)
calculus
Trace: 19.
null
mat_0327
worked_example
en
Compute the trace of [[9,0],[0,10]].
[ "Sum diagonal.", "9 + 10.", "= 19." ]
math
Answer: Trace: 19. Steps: 1. Sum diagonal. 2. 9 + 10. 3. = 19.
linear_algebra
Střední hodnota průměruje výsledky a předpovídá dlouhodobé chování.
null
mat_0328
concept
cs
Proč střední hodnota?
[ "Střední hodnota průměruje výsledky a předpovídá dlouhodobé chování.", "Odpověď tedy platí: Střední hodnota průměruje výsledky a předpovídá dlouhodobé chování." ]
math
Answer: Střední hodnota průměruje výsledky a předpovídá dlouhodobé chování. Steps: 1. Střední hodnota průměruje výsledky a předpovídá dlouhodobé chování. 2. Odpověď tedy platí: Střední hodnota průměruje výsledky a předpovídá dlouhodobé chování.
probability
The gcd is 15.
{ "A": "12", "B": "18", "C": "21", "D": "15" }
mat_0329
multiple_choice
en
Find gcd(30, 45).
[ "Factor 3 out twice.", "gcd = 15.", "Select option D." ]
math
Answer: 15 Steps: 1. Factor 3 out twice. 2. gcd = 15. 3. Select option D. Answer: (D)
number_theory
Closed forms compute terms fast, skipping step-by-step iteration entirely.
null
mat_0330
concept
en
Why solve recurrences?
[ "Closed forms compute terms fast, skipping step-by-step iteration entirely.", "So the answer stands: Closed forms compute terms fast, skipping step-by-step iteration entirely." ]
math
Answer: Closed forms compute terms fast, skipping step-by-step iteration entirely. Steps: 1. Closed forms compute terms fast, skipping step-by-step iteration entirely. 2. So the answer stands: Closed forms compute terms fast, skipping step-by-step iteration entirely.
combinatorics
Rows: 256.
null
mat_0331
worked_example
en
A proof checks all cases of 8 boolean variables. How many rows?
[ "2 choices each.", "2^8 = 256." ]
math
Answer: Rows: 256. Steps: 1. 2 choices each. 2. 2^8 = 256.
proofs
The ratio test compares successive terms, and a limit below one guarantees absolute convergence.
null
mat_0332
concept
en
What is the ratio test?
[ "The ratio test compares successive terms, and a limit below one guarantees absolute convergence.", "So the answer stands: The ratio test compares successive terms, and a limit below one guarantees absolute convergence." ]
math
Answer: The ratio test compares successive terms, and a limit below one guarantees absolute convergence. Steps: 1. The ratio test compares successive terms, and a limit below one guarantees absolute convergence. 2. So the answer stands: The ratio test compares successive terms, and a limit below one guarantees absolute...
calculus
The answer is Its inverse.
{ "A": "Its transpose", "B": "Its inverse", "C": "Its trace", "D": "Its copy" }
mat_0333
multiple_choice
en
Choose: what undoes a matrix?
[ "Product is identity.", "So: Its inverse.", "Select option B." ]
math
Answer: Its inverse Steps: 1. Product is identity. 2. So: Its inverse. 3. Select option B. Answer: (B)
linear_algebra
It brackets the true parameter with stated confidence, quantifying statistical uncertainty.
null
mat_0334
concept
en
What is a confidence interval?
[ "It brackets the true parameter with stated confidence, quantifying statistical uncertainty.", "So the answer stands: It brackets the true parameter with stated confidence, quantifying statistical uncertainty." ]
math
Answer: It brackets the true parameter with stated confidence, quantifying statistical uncertainty. Steps: 1. It brackets the true parameter with stated confidence, quantifying statistical uncertainty. 2. So the answer stands: It brackets the true parameter with stated confidence, quantifying statistical uncertainty.
probability
The remainder is 4.
{ "A": "4", "B": "5", "C": "6", "D": "7" }
mat_0335
multiple_choice
en
Find (121) mod 9.
[ "121 ÷ 9.", "Remainder 4.", "Select option A." ]
math
Answer: 4 Steps: 1. 121 ÷ 9. 2. Remainder 4. 3. Select option A. Answer: (A)
number_theory
C(11,2) = 55.
null
mat_0336
worked_example
en
Show the computation of C(11,2).
[ "Formula n(n−1)/2.", "11×10/2.", "= 55." ]
math
Answer: C(11,2) = 55. Steps: 1. Formula n(n−1)/2. 2. 11×10/2. 3. = 55.
combinatorics
Sum: 78.
null
mat_0337
worked_example
en
Prove by formula: find the sum 1 + 2 + ... + 12.
[ "Pair 1+12, 2+11, ...", "Use 12×13/2.", "= 78." ]
math
Answer: Sum: 78. Steps: 1. Pair 1+12, 2+11, ... 2. Use 12×13/2. 3. = 78.
proofs
Integral: 729.
null
mat_0338
worked_example
en
Evaluate the integral of 3x² from 0 to 9.
[ "Antiderivative: x³.", "Evaluate 0 to 9.", "9³ − 0 = 729." ]
math
Answer: Integral: 729. Steps: 1. Antiderivative: x³. 2. Evaluate 0 to 9. 3. 9³ − 0 = 729.
calculus
The answer is Null space.
{ "A": "Top row", "B": "Last column", "C": "Null space", "D": "Big entry" }
mat_0339
multiple_choice
en
Choose: what holds map-to-zero?
[ "Collapse measured.", "So: Null space.", "Select option C." ]
math
Answer: Null space Steps: 1. Collapse measured. 2. So: Null space. 3. Select option C. Answer: (C)
linear_algebra
Testing weighs evidence against a null claim, rejecting it only when data is extreme.
null
mat_0340
concept
en
Why hypothesis testing?
[ "Testing weighs evidence against a null claim, rejecting it only when data is extreme.", "So the answer stands: Testing weighs evidence against a null claim, rejecting it only when data is extreme." ]
math
Answer: Testing weighs evidence against a null claim, rejecting it only when data is extreme. Steps: 1. Testing weighs evidence against a null claim, rejecting it only when data is extreme. 2. So the answer stands: Testing weighs evidence against a null claim, rejecting it only when data is extreme.
probability
Odpověď je prvočísla.
{ "A": "sudá čísla", "B": "čtverce", "C": "krychle", "D": "prvočísla" }
mat_0341
multiple_choice
cs
Vyber: co jsou atomy násobení?
[ "Jednoznačný rozklad.", "Tedy: prvočísla.", "Vyber možnost D." ]
math
Answer: prvočísla Steps: 1. Jednoznačný rozklad. 2. Tedy: prvočísla. 3. Vyber možnost D. Answer: (D)
number_theory
Each term sums the prior two from 1,1, growing exponentially with golden ratio ties.
null
mat_0342
concept
en
What is the Fibonacci sequence?
[ "Each term sums the prior two from 1,1, growing exponentially with golden ratio ties.", "So the answer stands: Each term sums the prior two from 1,1, growing exponentially with golden ratio ties." ]
math
Answer: Each term sums the prior two from 1,1, growing exponentially with golden ratio ties. Steps: 1. Each term sums the prior two from 1,1, growing exponentially with golden ratio ties. 2. So the answer stands: Each term sums the prior two from 1,1, growing exponentially with golden ratio ties.
combinatorics
Half: 36, so 72 is even.
null
mat_0343
worked_example
en
Show N² + N is even for N = 8 by computing its half.
[ "8² + 8 = 72.", "72 / 2 = 36.", "Integer, so even." ]
math
Answer: Half: 36, so 72 is even. Steps: 1. 8² + 8 = 72. 2. 72 / 2 = 36. 3. Integer, so even.
proofs
Limit: 18.
null
mat_0344
worked_example
en
Evaluate the limit of (x² − 9²)/(x − 9) as x → 9.
[ "Factor: (x−9)(x+9).", "Cancel (x−9).", "Plug 9: 9+9 = 18." ]
math
Answer: Limit: 18. Steps: 1. Factor: (x−9)(x+9). 2. Cancel (x−9). 3. Plug 9: 9+9 = 18.
calculus
Dot product: 59.
null
mat_0345
worked_example
en
Compute (8,7) · (3,5) step by step.
[ "Multiply components.", "8×3 + 7×5.", "= 59." ]
math
Answer: Dot product: 59. Steps: 1. Multiply components. 2. 8×3 + 7×5. 3. = 59.
linear_algebra
The answer is Bayes' theorem.
{ "A": "Coin toss", "B": "Bayes' theorem", "C": "Dice roll", "D": "Card draw" }
mat_0346
multiple_choice
en
Choose: what flips conditionals?
[ "Causes from effects.", "So: Bayes' theorem.", "Select option B." ]
math
Answer: Bayes' theorem Steps: 1. Causes from effects. 2. So: Bayes' theorem. 3. Select option B. Answer: (B)
probability
phi(n) counts numbers below n coprime to it, measuring reduced residue systems.
null
mat_0347
concept
en
What is the totient?
[ "phi(n) counts numbers below n coprime to it, measuring reduced residue systems.", "So the answer stands: phi(n) counts numbers below n coprime to it, measuring reduced residue systems." ]
math
Answer: phi(n) counts numbers below n coprime to it, measuring reduced residue systems. Steps: 1. phi(n) counts numbers below n coprime to it, measuring reduced residue systems. 2. So the answer stands: phi(n) counts numbers below n coprime to it, measuring reduced residue systems.
number_theory
The answer is Inclusion-exclusion.
{ "A": "More counting", "B": "Inclusion-exclusion", "C": "Less thinking", "D": "Wild hope" }
mat_0348
multiple_choice
en
Choose: what fixes double-counting?
[ "Alternate the sums.", "So: Inclusion-exclusion.", "Select option B." ]
math
Answer: Inclusion-exclusion Steps: 1. Alternate the sums. 2. So: Inclusion-exclusion. 3. Select option B. Answer: (B)
combinatorics
The table has 32 rows.
{ "A": "30", "B": "34", "C": "36", "D": "32" }
mat_0349
multiple_choice
en
How many rows does a truth table with 5 variables have?
[ "2^5 rows.", "Total: 32.", "Select option D." ]
math
Answer: 32 Steps: 1. 2^5 rows. 2. Total: 32. 3. Select option D. Answer: (D)
proofs
f'(3) = 26.
null
mat_0350
worked_example
en
For f(x) = 3x² + 8x, compute f'(3) step by step.
[ "f'(x) = 6x + 8.", "Plug x = 3.", "6×3 + 8 = 26." ]
math
Answer: f'(3) = 26. Steps: 1. f'(x) = 6x + 8. 2. Plug x = 3. 3. 6×3 + 8 = 26.
calculus