What is 2/8 of 18?
Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 2/8 of 18? We'll show you a straightforward method to achieve that.
How to calculate 2/8 of 18?
- Multiply the whole number by the numerator of the fraction: 18 × 2 = 36
- Divide this result by denominator of the fraction: 36/8 = 4.5
- Simplify by dividing both the numerator and denominator by their GCD (4):
- 36/4 = 9
- 8/4 = 2
- Which gives: 9/2
Since 9/2 is an improper fraction, the result could also be expressed as a mixed number: 4 1/2
How does it work?
The principle behind finding a fraction of a number, such as 2/8 of 18, is rooted in the method of cross-multiplication.
Consider the following proportion: (where x represents 2/8 of 18)
- Using the cross-multiplication method, multiply both numerators by their opposite denominators:
- Which gives:
- Divide both sides by 8 to isolate x:
- Which gives the result: (or )
Thus, 2/8 of 18 is equal to 9/2 (or 4.5 in its decimal form).