Subtract 3/21 from 42/40
1st number: 1 2/40, 2nd number: 3/21
42/40 - 3/21 is 127/140.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 21 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 40 × 21 = 840,
42/40 = 42 × 21/40 × 21 = 882/840 - Likewise, for the 2nd fraction, since 21 × 40 = 840,
3/21 = 3 × 40/21 × 40 = 120/840 - Subtract the two like fractions:
882/840 - 120/840 = 882 - 120/840 = 762/840 - After reducing the fraction, the answer is 127/140
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/40-3/21 42/40-6/21 42/80-3/21 42/40-3/42 42/40-9/21 42/40-3/63 42/40-15/21