What is 9/7 of 40?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 9/7 of 40? We'll show you a straightforward method to achieve that.

How to calculate 9/7 of 40?

  1. Multiply the whole number by the numerator of the fraction: 40 × 9 = 360
  2. Divide this result by denominator of the fraction: 360/7 = 51.428571428571

Since 360/7 is an improper fraction, the result could also be expressed as a mixed number: 51 3/7

How does it work?

The principle behind finding a fraction of a number, such as 9/7 of 40, is rooted in the method of cross-multiplication.

Consider the following proportion: 9 7 = x 40 (where x represents 9/7 of 40)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 9 × 40 = 7 x
  2. Which gives: 360 = 7 x
  3. Divide both sides by 7 to isolate x: 360 7 = 7 x 7
  4. Which gives the result: 360 7 = x

Thus, 9/7 of 40 is equal to 360/7 (or 51.428571428571 in its decimal form).