Subtract 21/9 from 84/42
1st number: 2 0/42, 2nd number: 2 3/9
84/42 - 21/9 is -1/3.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 9 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 42 × 3 = 126,
84/42 = 84 × 3/42 × 3 = 252/126 - Likewise, for the 2nd fraction, since 9 × 14 = 126,
21/9 = 21 × 14/9 × 14 = 294/126 - Subtract the two like fractions:
252/126 - 294/126 = 252 - 294/126 = -42/126 - After reducing the fraction, the answer is -1/3
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/42-42/9 84/42-21/18 84/42-63/9 84/42-21/27 84/42-21/45 84/42-21/63