What is 1/2 of 31?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 1/2 of 31? We'll show you a straightforward method to achieve that.

How to calculate 1/2 of 31?

  1. Multiply the whole number by the numerator of the fraction: 31 × 1 = 31
  2. Divide this result by denominator of the fraction: 31/2 = 15.5

Since 31/2 is an improper fraction, the result could also be expressed as a mixed number: 15 1/2

How does it work?

The principle behind finding a fraction of a number, such as 1/2 of 31, is rooted in the method of cross-multiplication.

Consider the following proportion: 1 2 = x 31 (where x represents 1/2 of 31)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 1 × 31 = 2 x
  2. Which gives: 31 = 2 x
  3. Divide both sides by 2 to isolate x: 31 2 = 2 x 2
  4. Which gives the result: 31 2 = x

Thus, 1/2 of 31 is equal to 31/2 (or 15.5 in its decimal form).