What is 1/8 of 42?

How to calculate 1/8 of 42?

1. Multiply the whole number by the numerator of the fraction: 42 × 1 = 42
2. Divide this result by denominator of the fraction: 42/8 = 5.25
3. Simplify by dividing both the numerator and denominator by their GCD (2):
   • 42/2 = 21
   • 8/2 = 4
4. Which gives: 21/4

Since 21/4 is an improper fraction, the result could also be expressed as a mixed number: 5 1/4

How does it work?

The principle behind finding a fraction of a number, such as 1/8 of 42, is rooted in the method of cross-multiplication.

Consider the following proportion: $\frac{1}{8}=\frac{x}{42}$ (where x represents 1/8 of 42)

1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: $1\times 42=8x$
2. Which gives: $42=8x$
3. Divide both sides by 8 to isolate x: $\frac{42}{8}=\frac{8x}{8}$
4. Which gives the result: $\frac{42}{8}=x$ (or $\frac{21}{4}=x$)

Thus, 1/8 of 42 is equal to 21/4 (or 5.25 in its decimal form).