What is 9/10 of 39?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 9/10 of 39? We'll show you a straightforward method to achieve that.

How to calculate 9/10 of 39?

  1. Multiply the whole number by the numerator of the fraction: 39 × 9 = 351
  2. Divide this result by denominator of the fraction: 351/10 = 35.1

Since 351/10 is an improper fraction, the result could also be expressed as a mixed number: 35 1/10

How does it work?

The principle behind finding a fraction of a number, such as 9/10 of 39, is rooted in the method of cross-multiplication.

Consider the following proportion: 9 10 = x 39 (where x represents 9/10 of 39)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 9 × 39 = 10 x
  2. Which gives: 351 = 10 x
  3. Divide both sides by 10 to isolate x: 351 10 = 10 x 10
  4. Which gives the result: 351 10 = x

Thus, 9/10 of 39 is equal to 351/10 (or 35.1 in its decimal form).