ELI5: Explain Like I'm 5

Multiplicative inverse

A multiplicative inverse is a number that, when multiplied with the original number, equals 1. For example, the multiplicative inverse of 4 is 1/4 because 4 x 1/4 = 1. Another example is the multiplicative inverse of 5 is 1/5 because 5 x 1/5 = 1.