Subtract 42/40 from 21/7
1st number: 3 0/7, 2nd number: 1 2/40
21/7 - 42/40 is 39/20.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 7 and 40 is 280
Next, find the equivalent fraction of both fractional numbers with denominator 280 - For the 1st fraction, since 7 × 40 = 280,
21/7 = 21 × 40/7 × 40 = 840/280 - Likewise, for the 2nd fraction, since 40 × 7 = 280,
42/40 = 42 × 7/40 × 7 = 294/280 - Subtract the two like fractions:
840/280 - 294/280 = 840 - 294/280 = 546/280 - After reducing the fraction, the answer is 39/20
- In mixed form: 119/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/7-42/40 21/7-84/40 21/14-42/40 21/7-42/80 63/7-42/40 21/35-42/40 21/49-42/40