A letter or symbol used to represent an unknown quantity.

An expression that includes a variable.

A number whose whole number part and the fractional part is separated by a decimal point.

Two or more numbers that are multiplied to give a product.

The result of multiplying.

To replace a variable with a number in an expression, equation, or inequality.

A number that tells how many times another number, called the base, is used as a factor.

The order in which operations in an expression must be performed when more than one operation is involved.

Mathematical operations that undo each other.

A whole number greater than 1 that has exactly two factors, itself and 1.