What is 3/6 of 81?

How to calculate 3/6 of 81?

1. Multiply the whole number by the numerator of the fraction: 81 × 3 = 243
2. Divide this result by denominator of the fraction: 243/6 = 40.5
3. Simplify by dividing both the numerator and denominator by their GCD (3):
   • 243/3 = 81
   • 6/3 = 2
4. Which gives: 81/2

Since 81/2 is an improper fraction, the result could also be expressed as a mixed number: 40 1/2

How does it work?

The principle behind finding a fraction of a number, such as 3/6 of 81, is rooted in the method of cross-multiplication.

Consider the following proportion: $\frac{3}{6}=\frac{x}{81}$ (where x represents 3/6 of 81)

1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: $3\times 81=6x$
2. Which gives: $243=6x$
3. Divide both sides by 6 to isolate x: $\frac{243}{6}=\frac{6x}{6}$
4. Which gives the result: $\frac{243}{6}=x$ (or $\frac{81}{2}=x$)

Thus, 3/6 of 81 is equal to 81/2 (or 40.5 in its decimal form).