What is 10/8 of 78?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 10/8 of 78? We'll show you a straightforward method to achieve that.

How to calculate 10/8 of 78?

  1. Multiply the whole number by the numerator of the fraction: 78 × 10 = 780
  2. Divide this result by denominator of the fraction: 780/8 = 97.5
  3. Simplify by dividing both the numerator and denominator by their GCD (4):
    • 780/4 = 195
    • 8/4 = 2
  4. Which gives: 195/2

Since 195/2 is an improper fraction, the result could also be expressed as a mixed number: 97 1/2

How does it work?

The principle behind finding a fraction of a number, such as 10/8 of 78, is rooted in the method of cross-multiplication.

Consider the following proportion: 10 8 = x 78 (where x represents 10/8 of 78)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 10 × 78 = 8 x
  2. Which gives: 780 = 8 x
  3. Divide both sides by 8 to isolate x: 780 8 = 8 x 8
  4. Which gives the result: 780 8 = x (or 195 2 = x )

Thus, 10/8 of 78 is equal to 195/2 (or 97.5 in its decimal form).