What is 1/8 of 18?

How to calculate 1/8 of 18?

1. Multiply the whole number by the numerator of the fraction: 18 × 1 = 18
2. Divide this result by denominator of the fraction: 18/8 = 2.25
3. Simplify by dividing both the numerator and denominator by their GCD (2):
   • 18/2 = 9
   • 8/2 = 4
4. Which gives: 9/4

Since 9/4 is an improper fraction, the result could also be expressed as a mixed number: 2 1/4

How does it work?

The principle behind finding a fraction of a number, such as 1/8 of 18, is rooted in the method of cross-multiplication.

Consider the following proportion: $\frac{1}{8}=\frac{x}{18}$ (where x represents 1/8 of 18)

1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: $1\times 18=8x$
2. Which gives: $18=8x$
3. Divide both sides by 8 to isolate x: $\frac{18}{8}=\frac{8x}{8}$
4. Which gives the result: $\frac{18}{8}=x$ (or $\frac{9}{4}=x$)

Thus, 1/8 of 18 is equal to 9/4 (or 2.25 in its decimal form).