What is 5/4 of 84?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 5/4 of 84? We'll show you a straightforward method to achieve that.

How to calculate 5/4 of 84?

  1. Multiply the whole number by the numerator of the fraction: 84 × 5 = 420
  2. Divide this result by denominator of the fraction: 420/4 = 105
  3. Simplify by dividing both the numerator and denominator by their GCD (4):
    • 420/4 = 105
    • 4/4 = 1
  4. Which gives: 105/1

How does it work?

The principle behind finding a fraction of a number, such as 5/4 of 84, is rooted in the method of cross-multiplication.

Consider the following proportion: 5 4 = x 84 (where x represents 5/4 of 84)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 5 × 84 = 4 x
  2. Which gives: 420 = 4 x
  3. Divide both sides by 4 to isolate x: 420 4 = 4 x 4
  4. Which gives the result: 420 4 = x (or 105 1 = x )

Thus, 5/4 of 84 is equal to 105/1 (or 105 in its decimal form).