What is 5/2 of 87?

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 87? We'll show you a straightforward method to achieve that.

How to calculate 5/2 of 87?

  1. Multiply the whole number by the numerator of the fraction: 87 × 5 = 435
  2. Divide this result by denominator of the fraction: 435/2 = 217.5

Since 435/2 is an improper fraction, the result could also be expressed as a mixed number: 217 1/2

How does it work?

The principle behind finding a fraction of a number, such as 5/2 of 87, is rooted in the method of cross-multiplication.

Consider the following proportion: 5 2 = x 87 (where x represents 5/2 of 87)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 5 × 87 = 2 x
  2. Which gives: 435 = 2 x
  3. Divide both sides by 2 to isolate x: 435 2 = 2 x 2
  4. Which gives the result: 435 2 = x

Thus, 5/2 of 87 is equal to 435/2 (or 217.5 in its decimal form).