What is 3/6 of 78?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 3/6 of 78? We'll show you a straightforward method to achieve that.

How to calculate 3/6 of 78?

  1. Multiply the whole number by the numerator of the fraction: 78 × 3 = 234
  2. Divide this result by denominator of the fraction: 234/6 = 39
  3. Simplify by dividing both the numerator and denominator by their GCD (6):
    • 234/6 = 39
    • 6/6 = 1
  4. Which gives: 39/1

How does it work?

The principle behind finding a fraction of a number, such as 3/6 of 78, is rooted in the method of cross-multiplication.

Consider the following proportion: 3 6 = x 78 (where x represents 3/6 of 78)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 3 × 78 = 6 x
  2. Which gives: 234 = 6 x
  3. Divide both sides by 6 to isolate x: 234 6 = 6 x 6
  4. Which gives the result: 234 6 = x (or 39 1 = x )

Thus, 3/6 of 78 is equal to 39/1 (or 39 in its decimal form).