### Key Terms

- absolute value
- The absolute value of a number is its distance from $0$ on the number line.

- additive identity
- The number 0 is the additive identity because adding 0 to any number does not change its value.

- additive inverse
- The opposite of a number is its additive inverse.

- coefficient
- The coefficient of a term is the constant that multiplies the variable in a term.

- complex fraction
- A fraction in which the numerator or the denominator is a fraction is called a complex fraction.

- composite number
- A composite number is a counting number that is not prime. It has factors other than 1 and the number itself.

- constant
- A constant is a number whose value always stays the same.

- denominator
- In a fraction, written $\frac{a}{b},$ where $b\xe2\u20300,$ the denominator
*b*is the number of equal parts the whole has been divided into.

- divisible by a number
- If a number
*m*is a multiple of*n*, then*m*is divisible by*n*.

- equation
- An equation is two expressions connected by an equal sign.

- equivalent fractions
- Equivalent fractions are fractions that have the same value.

- evaluate an expression
- To evaluate an expression means to find the value of the expression when the variables are replaced by a given number.

- expression
- An expression is a number, a variable, or a combination of numbers and variables using operation symbols.

- factors
- If $a\xc2\xb7b=m,$ then
*a*and*b*are factors of*m*.

- fraction
- A fraction is written $\frac{a}{b},$ where $b\xe2\u20300,$ and
*a*is the numerator and*b*is the denominator. A fraction represents parts of a whole.

- integers
- The whole numbers and their opposites are called the integers.

- irrational number
- An irrational number is a number that cannot be written as the ratio of two integers. Its decimal form does not stop and does not repeat.

- least common denominator
- The least common denominator (LCD) of two fractions is the least common multiple (LCM) of their denominators.

- least common multiple
- The least common multiple (LCM) of two numbers is the smallest number that is a multiple of both numbers.

- like terms
- Terms that are either constants or have the same variables raised to the same powers are called like terms.

- multiple of a number
- A number is a multiple of
*n*if it is the product of a counting number and*n.*

- multiplicative identity
- The number 1 is the multiplicative identity because multiplying 1 by any number does not change its value.

- multiplicative inverse
- The reciprocal of a number is its multiplicative inverse.

- negative numbers
- Numbers less than $0$ are negative numbers.

- numerator
- In a fraction, written $\frac{a}{b},$ where $b\xe2\u20300,$ the numerator
*a*indicates how many parts are included.

- opposite
- The opposite of a number is the number that is the same distance from zero on the number line but on the opposite side of zero.

- order of operations
- The order of operations are established guidelines for simplifying an expression.

- percent
- A percent is a ratio whose denominator is 100.

- prime factorization
- The prime factorization of a number is the product of prime numbers that equals the number.

- prime number
- A prime number is a counting number greater than 1 whose only factors are 1 and the number itself.

- principal square root
- The positive square root is called the principal square root.

- rational number
- A rational number is a number of the form $\frac{p}{q},$ where
*p*and*q*are integers and $q\xe2\u20300.$ Its decimal form stops or repeats.

- real number
- A real number is a number that is either rational or irrational.

- reciprocal
- The reciprocal of a fraction is found by inverting the fraction, placing the numerator in the denominator and the denominator in the numerator.

- simplify an expression
- To simplify an expression means to do all the math possible.

- square of a number
- If ${n}^{2}=m,$ then
*m*is the square of*n*.

- square root of a number
- If ${n}^{2}=m,$ then
*n*is a square root of*m*.

- term
- A term is a constant, or the product of a constant and one or more variables.

- variable
- A variable is a letter that represents a number whose value may change.