The reciprocal or multiplicative inverse of a number x is the number which, when multiplied by x, gives 1.
So, the product of a number and its reciprocal is 1. (This is sometimes called the property of reciprocals.)
so the reciprocal of 3 is (and the reciprocal of is 3.)
so and are reciprocals.
Note that zero has no reciprocal.
Reciprocals are used to solve simple linear equations, for instance:
To solve, multiply both sides by the reciprocal of .