Fractions must share a common denominator in order to be added or subtracted. The common denominator is the least common multiple of all the denominators.

To raise a term with an exponent to another exponent, retain the base and multiply the exponents: (x²)³ = x^(2x3) = x⁶

The least common multiple (LCM) is the smallest positive integer that is a multiple of two or more integers.

Percentages are ratios of an amount compared to 100. The percent change of an old to new value is equal to 100% x \({ new - old \over old }\).

A prime number is an integer greater than 1 that has no factors other than 1 and itself. Examples of prime numbers include 2, 3, 5, 7, and 11.