Subtract 21/7 from 12/40
1st number: 12/40, 2nd number: 3 0/7
12/40 - 21/7 is -27/10.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 7 is 280
Next, find the equivalent fraction of both fractional numbers with denominator 280 - For the 1st fraction, since 40 × 7 = 280,
12/40 = 12 × 7/40 × 7 = 84/280 - Likewise, for the 2nd fraction, since 7 × 40 = 280,
21/7 = 21 × 40/7 × 40 = 840/280 - Subtract the two like fractions:
84/280 - 840/280 = 84 - 840/280 = -756/280 - After reducing the fraction, the answer is -27/10
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/40-21/7 12/40-42/7 12/80-21/7 12/40-21/14 36/40-21/7 12/40-63/7 60/40-21/7 12/40-21/35 84/40-21/7 12/40-21/49