Subtract 21/9 from 30/42
1st number: 30/42, 2nd number: 2 3/9
30/42 - 21/9 is -34/21.
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,
30/42 = 30 × 3/42 × 3 = 90/126 - Likewise, for the 2nd fraction, since 9 × 14 = 126,
21/9 = 21 × 14/9 × 14 = 294/126 - Subtract the two like fractions:
90/126 - 294/126 = 90 - 294/126 = -204/126 - After reducing the fraction, the answer is -34/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/42-21/9 30/42-42/9 30/84-21/9 30/42-21/18 90/42-21/9 30/42-63/9 30/42-21/27 30/42-21/45 30/42-21/63