What is 2/5 of 4?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 2/5 of 4? We'll show you a straightforward method to achieve that.

How to calculate 2/5 of 4?

  1. Multiply the whole number by the numerator of the fraction: 4 × 2 = 8
  2. Divide this result by denominator of the fraction: 8/5 = 1.6

Since 8/5 is an improper fraction, the result could also be expressed as a mixed number: 1 3/5

How does it work?

The principle behind finding a fraction of a number, such as 2/5 of 4, is rooted in the method of cross-multiplication.

Consider the following proportion: 2 5 = x 4 (where x represents 2/5 of 4)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 2 × 4 = 5 x
  2. Which gives: 8 = 5 x
  3. Divide both sides by 5 to isolate x: 8 5 = 5 x 5
  4. Which gives the result: 8 5 = x

Thus, 2/5 of 4 is equal to 8/5 (or 1.6 in its decimal form).