What is 3/5 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 3/5 of 70? We'll show you a straightforward method to achieve that.

How to calculate 3/5 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: 210/5 = 42
  3. Simplify by dividing both the numerator and denominator by their GCD (5):
    • 210/5 = 42
    • 5/5 = 1
  4. Which gives: 42/1

How does it work?

The principle behind finding a fraction of a number, such as 3/5 of 70, is rooted in the method of cross-multiplication.

Consider the following proportion: 3 5 = x 70 (where x represents 3/5 of 70)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 3 × 70 = 5 x
  2. Which gives: 210 = 5 x
  3. Divide both sides by 5 to isolate x: 210 5 = 5 x 5
  4. Which gives the result: 210 5 = x (or 42 1 = x )

Thus, 3/5 of 70 is equal to 42/1 (or 42 in its decimal form).