Subtract 12/7 from 21/30
1st number: 21/30, 2nd number: 1 5/7
21/30 - 12/7 is -71/70.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 7 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 30 × 7 = 210,
21/30 = 21 × 7/30 × 7 = 147/210 - Likewise, for the 2nd fraction, since 7 × 30 = 210,
12/7 = 12 × 30/7 × 30 = 360/210 - Subtract the two like fractions:
147/210 - 360/210 = 147 - 360/210 = -213/210 - After reducing the fraction, the answer is -71/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/30-12/7 21/30-24/7 21/60-12/7 21/30-12/14 63/30-12/7 21/30-36/7 21/90-12/7 21/30-12/21 21/30-60/7 21/30-12/35 21/30-84/7 21/30-12/49