What is 8/9 of 18?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 8/9 of 18? We'll show you a straightforward method to achieve that.

How to calculate 8/9 of 18?

  1. Multiply the whole number by the numerator of the fraction: 18 × 8 = 144
  2. Divide this result by denominator of the fraction: 144/9 = 16
  3. Simplify by dividing both the numerator and denominator by their GCD (9):
    • 144/9 = 16
    • 9/9 = 1
  4. Which gives: 16/1

How does it work?

The principle behind finding a fraction of a number, such as 8/9 of 18, is rooted in the method of cross-multiplication.

Consider the following proportion: 8 9 = x 18 (where x represents 8/9 of 18)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 8 × 18 = 9 x
  2. Which gives: 144 = 9 x
  3. Divide both sides by 9 to isolate x: 144 9 = 9 x 9
  4. Which gives the result: 144 9 = x (or 16 1 = x )

Thus, 8/9 of 18 is equal to 16/1 (or 16 in its decimal form).