What is 7/10 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 7/10 of 57? We'll show you a straightforward method to achieve that.

How to calculate 7/10 of 57?

  1. Multiply the whole number by the numerator of the fraction: 57 × 7 = 399
  2. Divide this result by denominator of the fraction: 399/10 = 39.9

Since 399/10 is an improper fraction, the result could also be expressed as a mixed number: 39 9/10

How does it work?

The principle behind finding a fraction of a number, such as 7/10 of 57, is rooted in the method of cross-multiplication.

Consider the following proportion: 7 10 = x 57 (where x represents 7/10 of 57)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 7 × 57 = 10 x
  2. Which gives: 399 = 10 x
  3. Divide both sides by 10 to isolate x: 399 10 = 10 x 10
  4. Which gives the result: 399 10 = x

Thus, 7/10 of 57 is equal to 399/10 (or 39.9 in its decimal form).