What is 5/7 of 51?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 5/7 of 51? We'll show you a straightforward method to achieve that.

How to calculate 5/7 of 51?

  1. Multiply the whole number by the numerator of the fraction: 51 × 5 = 255
  2. Divide this result by denominator of the fraction: 255/7 = 36.428571428571

Since 255/7 is an improper fraction, the result could also be expressed as a mixed number: 36 3/7

How does it work?

The principle behind finding a fraction of a number, such as 5/7 of 51, is rooted in the method of cross-multiplication.

Consider the following proportion: 5 7 = x 51 (where x represents 5/7 of 51)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 5 × 51 = 7 x
  2. Which gives: 255 = 7 x
  3. Divide both sides by 7 to isolate x: 255 7 = 7 x 7
  4. Which gives the result: 255 7 = x

Thus, 5/7 of 51 is equal to 255/7 (or 36.428571428571 in its decimal form).