What is 10/2 of 80?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 10/2 of 80? We'll show you a straightforward method to achieve that.

How to calculate 10/2 of 80?

  1. Multiply the whole number by the numerator of the fraction: 80 × 10 = 800
  2. Divide this result by denominator of the fraction: 800/2 = 400
  3. Simplify by dividing both the numerator and denominator by their GCD (2):
    • 800/2 = 400
    • 2/2 = 1
  4. Which gives: 400/1

How does it work?

The principle behind finding a fraction of a number, such as 10/2 of 80, is rooted in the method of cross-multiplication.

Consider the following proportion: 10 2 = x 80 (where x represents 10/2 of 80)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 10 × 80 = 2 x
  2. Which gives: 800 = 2 x
  3. Divide both sides by 2 to isolate x: 800 2 = 2 x 2
  4. Which gives the result: 800 2 = x (or 400 1 = x )

Thus, 10/2 of 80 is equal to 400/1 (or 400 in its decimal form).