What is 6/4 of 15?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 6/4 of 15? We'll show you a straightforward method to achieve that.

How to calculate 6/4 of 15?

  1. Multiply the whole number by the numerator of the fraction: 15 × 6 = 90
  2. Divide this result by denominator of the fraction: 90/4 = 22.5
  3. Simplify by dividing both the numerator and denominator by their GCD (2):
    • 90/2 = 45
    • 4/2 = 2
  4. Which gives: 45/2

Since 45/2 is an improper fraction, the result could also be expressed as a mixed number: 22 1/2

How does it work?

The principle behind finding a fraction of a number, such as 6/4 of 15, is rooted in the method of cross-multiplication.

Consider the following proportion: 6 4 = x 15 (where x represents 6/4 of 15)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 6 × 15 = 4 x
  2. Which gives: 90 = 4 x
  3. Divide both sides by 4 to isolate x: 90 4 = 4 x 4
  4. Which gives the result: 90 4 = x (or 45 2 = x )

Thus, 6/4 of 15 is equal to 45/2 (or 22.5 in its decimal form).