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d=aj−aij−id=aj−aij−i
https://openstax.org/books/contemporary-mathematics/pages/3-formula-review
a1=ai−d(i−1)a1=ai−d(i−1)
https://openstax.org/books/contemporary-mathematics/pages/3-formula-review
sn=n(a1+an2)sn=n(a1+an2)
https://openstax.org/books/contemporary-mathematics/pages/3-formula-review
an=a1rn−1an=a1rn−1
https://openstax.org/books/contemporary-mathematics/pages/3-formula-review
sn=a1(1−rn−11−r)sn=a1(1−rn−11−r)
https://openstax.org/books/contemporary-mathematics/pages/3-formula-review
an=a1rn−1an=a1rn−1
https://openstax.org/books/contemporary-mathematics/pages/3-formula-review
sn=a1(1−rn−11−r)sn=a1(1−rn−11−r)
https://openstax.org/books/contemporary-mathematics/pages/3-formula-review
The natural numbers can be categorized as 1, prime numbers, and composite numbers.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Prime numbers have as their only factors 1 and themselves.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Composite numbers have at least three distinct factors.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Composite numbers can be written in their prime factorization form, which is found by repeatedly factoring prime factors from the number.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
The greatest common divisor (GCD) of a set of numbers is the largest integer that divides all of the numbers in the set. The prime factorizations of the numbers can be used to identify the greatest common divisor.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
The least common multiple (LCM) of a set of numbers is the smallest integer that is divisible by all of the numbers in the set. The prime factorizations of the numbers can be used to identify the least common multiple.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
There are various ways that the GCD and LCM are applied.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
A set of numbers that can be built from the natural numbers are the integers, which consist of the natural numbers, zero (0), and the negatives of the natural numbers.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Integers are often graphed on a number line, which helps display the relative positions and values of those numbers.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
The number line can be used to visualize when one integer is larger than or smaller than another integer.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Arithmetic operations with integers are similar to the operations with natural numbers, except that the sign (positive or negative) of the numbers will determine the sign (positive or negative) of the result.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Establishing shared rules on which arithmetic operations are calculated first is necessary. Without them, different people may find different values for the same expression.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
The highest precedence is with expressions in parentheses. This allows parts of an expression to be calculated in an order different than the basic order of operations.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
The lowest precedence is addition and subtraction, as they are the basis for all other calculations.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Multiplication and division have precedence over addition and subtraction, as they are representations of repeated addition or subtraction.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Exponents have precedence over multiplication and division, as they represent repeated multiplication and division.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Rational numbers are fractions of integers, and can always be written as an integer divided by an integer.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
The numerator and denominator of a fraction may have common factors. In such cases, the fraction can be reduced by canceling common factors. When the numerator and denominator of a fraction have no common factors, the fraction is said to be reduced.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
An improper fraction is one with a numerator larger than the denominator. Such a fraction can be rewritten as an integer plus a proper fraction. This is called a mixed number.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Using division and remainder, an improper fraction may be written as a mixed number.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
A mixed number can be converted to an improper fraction by reversing the process for changing an improper fraction to a mixed number.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
The arithmetic operations or addition, subtraction, multiplication and division can all be performed on rational numbers.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Addition and subtraction of rational numbers can be performed after a common denominator has been identified, and the fractions have been converted to forms having the common denominator.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Multiplication and division of rational numbers can be performed without regard to common denominators.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Between any two rational numbers, there is always another rational number. This is the density property of the rational numbers.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Irrational numbers are numbers that cannot be written as an integer divided by another integer. One example is pi, denotedππ. Another collection of irrational numbers are natural numbers that are not perfect squares.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Some irrational numbers can be written as a rational part multiplied by an irrational part. If two irrational numbers have the same irrational parts, they can be added or subtracted.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
When irrational numbers are similar, on can multiply and divide the numbers without a calculator.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Sincea×b=a×ba×b=a×b, anda÷b=ab=aba÷b=ab=ab, products and quotients of square roots can be determined.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Becausea2=aa2=aanda×b=a×ba×b=a×b, it is possible to simplify square root expressions so the radicand contains no perfect square factors.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
When a fraction has an irrational number as its denominator, it is possible to convert the denominator into a rational number using its conjugate. Doing so involves multiplying the numerator and denominator by the conjugate of the denominator, and then applying the difference of squares formula.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
With a single square root term
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Using conjugate numbers for two term denominators
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Real numbers is the collection of all rational and irrational numbers. Conceptually, it is the collection of all values that can be represented on a number line, or, as a length along with sign.
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The subsets of the real numbers include the natural numbers, integers, rational numbers and irrational numbers. The natural numbers are a subset of the integers, which is a subset of the rational numbers. The rational and irrational numbers are disjoint sets.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
The real numbers, due to order of operation rules and that performing arithmetic operations on real number always results in a real number, have arithmetic properties that apply in all cases. There include the distributive property, the commutative property, and the associative property. Also, every real number has an ...
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Clock arithmetic uses the idea that after 12 o’clock comes 1 o’clock. For clock arithmetic, this means that every time 12 is passed in an arithmetic process, the next number is 1, not 13.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
To determine the clock result of an arithmetic operation, divide the final result by 12 and keep the remainder. If the remainder is 0, then the time is 12 o’clock.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Clock arithmetic is technically called modulo 12 arithmetic. To perform modulo 12 arithmetic, calculate the expression, then divide the result by 12. The modulo 12 result is the remainder.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Days, in our system, pass in groups of seven. To calculate in day arithmetic, modulo 7 is used. To perform modulo 7 arithmetic, calculate the expression, then divide the result by 7. The modulo 7 result is the remainder.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Exponents are used to express multiplying a number by itself a number of times. The number being multiplied by itself is the base. The number of times it is multiplied by itself is the exponent, which is often referred to as the power.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Understanding that exponents represent repeated multiplication of a base makes it possible to establish some rules for combining exponential expressions, using the product rule, the quotient rule, and the power rule. Additionally, it allows us to formulate distributive rules for exponents.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Any non-zero number raised to the 0th power is 1. This makes the definition of the 0th power consistent with the division rule for exponents.
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For consistency, negative exponents represent the reciprocal of the base raised to the power, so thata−n=1ana−n=1an, provided thataâ‰0aâ‰0.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Some numbers are so large or so small that writing the number out is clumsy and make it difficult to determine the true size of the number. Scientific notation makes the number more readable and make the relative size of the number immediately apparent.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
A number written in scientific notation is a number at least 1 and smaller than 10 multiplied by 10 raised to an exponent. Converting between scientific notation and standard notation involves correctly applying multiplication and division by powers of 10, which in practice equates to understanding how moving the decim...
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Adding and subtracting numbers in base 10 requires the exponent of 10 in each number be the same. Once the numbers are converted to have the same exponent with the ten, then the numbers are added or subtracted as indicated, with the power of 10 remaining the same. If the result is not in scientific notation (for instan...
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Multiplying and dividing numbers in scientific notation is done by multiplying or dividing the number parts, then multiplying or dividing the 10 raised to the power parts, then multiplying those two results. If the new number is not in scientific notation, then the result must be converted into scientific notation.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
A sequence is a list of numbers. Any individual number in that list, or sequence, is a term of the sequence. A specific term of a sequence is denoted by the sequence symbol with a subscript indicating where the term in the sequence is.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
A special form of a sequence is an arithmetic sequence. Each arithmetic sequence is determined by its first term and its constant difference. Any term in an arithmetic sequence is determined by adding the constant difference to the preceding term.
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If the first term and the constant difference of an arithmetic sequence are known, then any term of the sequence can be found directly.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Because arithmetic sequences follow such a strict pattern, the sum of the firstnnterms of an arithmetic sequence can be determined with the formulasn=n(a1+an2)sn=n(a1+an2).
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
A special form of a sequence is a geometric sequence. Each geometric sequence is determined by its first term and its constant ratio. Any term in a geometric sequence is determined by multiplying the constant ratio to the preceding term.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
If the first term and the constant ratio of a geometric sequence are known, then any term of the sequence can be found directly.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Because geometric sequences follow such a strict pattern, the sum of the firstnnterms of a geometric sequence can be determined with the formulasn=a1(1−rn−11−r)sn=a1(1−rn−11−r).
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Finding the sum of a finite geometric sequence
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Applying arithmetic sequences
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Geometric sequence.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Finding an arbitrary term in a geometric sequence.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Constant ratio.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Finding the sum of a finite geometric sequence.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Applying arithmetic sequences.
https://openstax.org/books/contemporary-mathematics/pages/3-key-concepts
Exponents are used to represent repeated multiplication of a base.
https://openstax.org/books/contemporary-mathematics/pages/4-key-concepts
In arithmetic, exponents are computed before multiplication, division, addition, and subtraction. Computing an exponent is done by multiplying the base by itself the number of times equal to the exponent.
https://openstax.org/books/contemporary-mathematics/pages/4-key-concepts
The system of numbers currently used is the Hindu-Arabic system. Digits in this system take on values based on their place in the number. The place values are determined by multiplying the digit by 10 raised to the appropriate power.
https://openstax.org/books/contemporary-mathematics/pages/4-key-concepts
The expanded form of a Hindu-Arabic number is the sum of each digit times 10 raised to the exponent for that place value.
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Historically, there have been many systems for numbering. One system is an additive system, in which symbols are repeated to express larger numbers. Another system is a positional system, in which the digits and their positions determine the quantity being represented.
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The Babylonian system was a combination of a positional and additive system. It used 60 as its base. Using that in the positional system makes it possible to convert between Babylonian and Hindu-Arabic numbers.
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The Mayan system was a combination of a positional and additive system. It used 20 as its base. Using that in the positional system makes it possible to convert between Mayan and Hindu-Arabic numbers.
https://openstax.org/books/contemporary-mathematics/pages/4-key-concepts
The Roman system was an additive system. Knowing what each symbol represents makes it possible to convert between Roman and Hindu-Arabic numbers.
https://openstax.org/books/contemporary-mathematics/pages/4-key-concepts
The system we use is the base 10 system. Base 10 is not the only base that can be used. To use another base, one could start with a list of numbers in that base.
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To indicate that a number is written in a base other than 10, a subscript is appended to the end of the number. That subscript indicates the base for the number.
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Numbers written in a base smaller than 10 use the same symbols as base 10. However, when using bases larger than 10, the symbols A, B, C, … are used to represent digits larger than 9.
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To convert from a number written in a base other than 10 into a base 10 number, the number is written in expanded form and then that expression is computed.
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To convert a number from base 10 into another base, the base 10 number is repeatedly divided by the new base. The remainders when performing these divisions become the digits for the number in the new base.
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Common errors can be detected when performing base conversions.
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Addition tables for bases other than 10 can be built using the same processes that are used in base 10, including using a number line.
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Addition in bases other than base 10 use the same processes as addition in base 10, but use the addition table for that base.
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Subtraction in bases other than base 10 use the same processes as subtraction in base 10, but use the addition table for that base.
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Multiplication tables for bases other than 10 can be built using the same processes that are used in base 10, including using repeated addition and the addition table for the base.
https://openstax.org/books/contemporary-mathematics/pages/4-key-concepts
Multiplication in bases other than base 10 use the same processes as multiplication in base 10, but use the multiplication table for that base.
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Basic division in bases other than base 10 use the same processes as basic division in base 10, where the missing factor process is used.
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Distributive Property:a(b+c)=ab+aca(b+c)=ab+ac
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For any numbersaa,bb, and,,ifa<ba<b, thena+c<b+ca+c<b+canda−c<b−ca−c<b−c.
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For any numbersaa,bb, andcc, ifa>ba>b, thena+c>b+ca+c>b+canda−c>b−ca−c>b−c.
https://openstax.org/books/contemporary-mathematics/pages/5-formula-review
For any numbersaa,bb, andcc,multiply or divide by a positive:ifa<ba<bandc>0c>0, thenac<bcac<bcandac<bcac<bcifa>ba>bandc>0c>0, thenac>bcac>bcandac>bcac>bcmultiply or divide by a negative:ifa<ba<bandc<0c<0, thenac>bcac>bcandac>bcac>bcifa>ba>bandc<0c<0, thenac<bcac<bcandac<bcac<bc
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To calculate slope(m)(m), use the formulam=riserunm=riserun,where the rise measures the vertical change and the run measures the horizontal change.
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To find the slope of the line between two points(x1,y1)(x1,y1)and(x2,y2)(x2,y2), use the formulam=y2−y1x2−x1m=y2−y1x2−x1
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Algebra is useful because it allows us to understand many situations in real life by modeling them with expressions.
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Algebraic expressions are the building blocks of algebra. From algebraic expressions we can create algebraic equations.
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Algebraic expressions are often simplified and evaluated using the four arithmetic operations.
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Solving linear equations means discovering what the value of the variable in a linear equation represents in the given conditions.
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When solving a linear equation, most often you will have one solution; however, a linear equation may have no solutions or infinitely many solutions.
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