What is 3/9 of 30?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 3/9 of 30? We'll show you a straightforward method to achieve that.

How to calculate 3/9 of 30?

  1. Multiply the whole number by the numerator of the fraction: 30 × 3 = 90
  2. Divide this result by denominator of the fraction: 90/9 = 10
  3. Simplify by dividing both the numerator and denominator by their GCD (9):
    • 90/9 = 10
    • 9/9 = 1
  4. Which gives: 10/1

How does it work?

The principle behind finding a fraction of a number, such as 3/9 of 30, is rooted in the method of cross-multiplication.

Consider the following proportion: 3 9 = x 30 (where x represents 3/9 of 30)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 3 × 30 = 9 x
  2. Which gives: 90 = 9 x
  3. Divide both sides by 9 to isolate x: 90 9 = 9 x 9
  4. Which gives the result: 90 9 = x (or 10 1 = x )

Thus, 3/9 of 30 is equal to 10/1 (or 10 in its decimal form).