What is 1/5 of 89?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 1/5 of 89? We'll show you a straightforward method to achieve that.

How to calculate 1/5 of 89?

  1. Multiply the whole number by the numerator of the fraction: 89 × 1 = 89
  2. Divide this result by denominator of the fraction: 89/5 = 17.8

Since 89/5 is an improper fraction, the result could also be expressed as a mixed number: 17 4/5

How does it work?

The principle behind finding a fraction of a number, such as 1/5 of 89, is rooted in the method of cross-multiplication.

Consider the following proportion: 1 5 = x 89 (where x represents 1/5 of 89)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 1 × 89 = 5 x
  2. Which gives: 89 = 5 x
  3. Divide both sides by 5 to isolate x: 89 5 = 5 x 5
  4. Which gives the result: 89 5 = x

Thus, 1/5 of 89 is equal to 89/5 (or 17.8 in its decimal form).