逆ぎゃく数すう

noun

reciprocal; multiplicative inverse

Mathematical term for the number which, when multiplied by the original number, yields 1. Used in arithmetic and algebra.

• 二にの逆ぎゃく数すうは二に分ぶんの一いちです。

  The reciprocal of 2 is one half.

• 分ぶん数すうの割わり算ざんでは、割わる数かずの逆ぎゃく数すうを掛かけます。

  In division of fractions, you multiply by the reciprocal of the divisor.