What is 8/7 of 21?

How to calculate 8/7 of 21?

1. Multiply the whole number by the numerator of the fraction: 21 × 8 = 168
2. Divide this result by denominator of the fraction: 168/7 = 24
3. Simplify by dividing both the numerator and denominator by their GCD (7):
   • 168/7 = 24
   • 7/7 = 1
4. Which gives: 24/1

How does it work?

The principle behind finding a fraction of a number, such as 8/7 of 21, is rooted in the method of cross-multiplication.

Consider the following proportion: $\frac{8}{7}=\frac{x}{21}$ (where x represents 8/7 of 21)

1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: $8\times 21=7x$
2. Which gives: $168=7x$
3. Divide both sides by 7 to isolate x: $\frac{168}{7}=\frac{7x}{7}$
4. Which gives the result: $\frac{168}{7}=x$ (or $\frac{24}{1}=x$)

Thus, 8/7 of 21 is equal to 24/1 (or 24 in its decimal form).