What is 5/2 of 57?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 5/2 of 57? We'll show you a straightforward method to achieve that.

How to calculate 5/2 of 57?

  1. Multiply the whole number by the numerator of the fraction: 57 × 5 = 285
  2. Divide this result by denominator of the fraction: 285/2 = 142.5

Since 285/2 is an improper fraction, the result could also be expressed as a mixed number: 142 1/2

How does it work?

The principle behind finding a fraction of a number, such as 5/2 of 57, is rooted in the method of cross-multiplication.

Consider the following proportion: 5 2 = x 57 (where x represents 5/2 of 57)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 5 × 57 = 2 x
  2. Which gives: 285 = 2 x
  3. Divide both sides by 2 to isolate x: 285 2 = 2 x 2
  4. Which gives the result: 285 2 = x

Thus, 5/2 of 57 is equal to 285/2 (or 142.5 in its decimal form).