What is 3/7 of 70?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 3/7 of 70? We'll show you a straightforward method to achieve that.

How to calculate 3/7 of 70?

  1. Multiply the whole number by the numerator of the fraction: 70 × 3 = 210
  2. Divide this result by denominator of the fraction: 210/7 = 30
  3. Simplify by dividing both the numerator and denominator by their GCD (7):
    • 210/7 = 30
    • 7/7 = 1
  4. Which gives: 30/1

How does it work?

The principle behind finding a fraction of a number, such as 3/7 of 70, is rooted in the method of cross-multiplication.

Consider the following proportion: 3 7 = x 70 (where x represents 3/7 of 70)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 3 × 70 = 7 x
  2. Which gives: 210 = 7 x
  3. Divide both sides by 7 to isolate x: 210 7 = 7 x 7
  4. Which gives the result: 210 7 = x (or 30 1 = x )

Thus, 3/7 of 70 is equal to 30/1 (or 30 in its decimal form).