What is 3/8 of 13?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 3/8 of 13? We'll show you a straightforward method to achieve that.

How to calculate 3/8 of 13?

  1. Multiply the whole number by the numerator of the fraction: 13 × 3 = 39
  2. Divide this result by denominator of the fraction: 39/8 = 4.875

Since 39/8 is an improper fraction, the result could also be expressed as a mixed number: 4 7/8

How does it work?

The principle behind finding a fraction of a number, such as 3/8 of 13, is rooted in the method of cross-multiplication.

Consider the following proportion: 3 8 = x 13 (where x represents 3/8 of 13)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 3 × 13 = 8 x
  2. Which gives: 39 = 8 x
  3. Divide both sides by 8 to isolate x: 39 8 = 8 x 8
  4. Which gives the result: 39 8 = x

Thus, 3/8 of 13 is equal to 39/8 (or 4.875 in its decimal form).