What is 3/8 of 100?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 3/8 of 100? We'll show you a straightforward method to achieve that.

How to calculate 3/8 of 100?

  1. Multiply the whole number by the numerator of the fraction: 100 × 3 = 300
  2. Divide this result by denominator of the fraction: 300/8 = 37.5
  3. Simplify by dividing both the numerator and denominator by their GCD (4):
    • 300/4 = 75
    • 8/4 = 2
  4. Which gives: 75/2

Since 75/2 is an improper fraction, the result could also be expressed as a mixed number: 37 1/2

How does it work?

The principle behind finding a fraction of a number, such as 3/8 of 100, is rooted in the method of cross-multiplication.

Consider the following proportion: 3 8 = x 100 (where x represents 3/8 of 100)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 3 × 100 = 8 x
  2. Which gives: 300 = 8 x
  3. Divide both sides by 8 to isolate x: 300 8 = 8 x 8
  4. Which gives the result: 300 8 = x (or 75 2 = x )

Thus, 3/8 of 100 is equal to 75/2 (or 37.5 in its decimal form).