What is 4/10 of 64?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 4/10 of 64? We'll show you a straightforward method to achieve that.

How to calculate 4/10 of 64?

  1. Multiply the whole number by the numerator of the fraction: 64 × 4 = 256
  2. Divide this result by denominator of the fraction: 256/10 = 25.6
  3. Simplify by dividing both the numerator and denominator by their GCD (2):
    • 256/2 = 128
    • 10/2 = 5
  4. Which gives: 128/5

Since 128/5 is an improper fraction, the result could also be expressed as a mixed number: 25 3/5

How does it work?

The principle behind finding a fraction of a number, such as 4/10 of 64, is rooted in the method of cross-multiplication.

Consider the following proportion: 4 10 = x 64 (where x represents 4/10 of 64)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 4 × 64 = 10 x
  2. Which gives: 256 = 10 x
  3. Divide both sides by 10 to isolate x: 256 10 = 10 x 10
  4. Which gives the result: 256 10 = x (or 128 5 = x )

Thus, 4/10 of 64 is equal to 128/5 (or 25.6 in its decimal form).