### Addition Property of Equality

For real numbers a, b, and c, if a = b, then a + c = b + c. In other words, adding the same number to each side of an equation produces an equivalent equation.

### Additive Inverse

The sum of a number and its additive inverse is zero. Also called the opposite of a number. Example: 5 and -5 are additive inverses of each other.

### Algebraic Expression

A mathematical phrase involving at least one variable. Expressions can contain numbers and operation symbols.

### Decimal Expression

The decimal expansion of a number is its representation in base 10 (i.e., the decimal system). For example, the decimal expansion of 252 is 625, of π is 3.14159..., and of 91 is 0.1111....

### Inverse Operation

Pairs of operations that undo each other, for example, addition and subtraction are inverse operations and multiplication and division are inverse operations.

### Irrational

A real number whose decimal form is non-terminating and non-repeating that cannot be written as the ratio of two integers.

### Like Terms

Monomials that have the same variable raised to the same power. Only the coefficients of like terms can be different.

### Linear Equation in One Variable

An equation that can be written in the form ax + b = c where a, b, and c are real numbers and a ≠ 0

### Multiplication Property of Equality

For real numbers a, b, and c (c ≠ 0), if a = b, then ac = bc. In other words, multiplying both sides of an equation by the same number produces an equivalent expression.

### Scientific Notation

A representation of real numbers as the product of a number between 1 and 10 and a power of 10, used primarily for very large or very small numbers.

### Solve

Identify the value that when substituted for the variable makes the equation a true statement.

### Square Root

One of two equal factors of a nonnegative number. For example, 5 is a square root of 25 because 5 • 5 = 25. Another square root of 25 is -5 because (-5) • (-5) = 25. The +5 is called the principle square root of 25 and is always assumed when the radical symbol is used.