Subtract 2/21 from 7/40
7/40 - 2/21 is 67/840.
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,
7/40 = 7 × 21/40 × 21 = 147/840 - Likewise, for the 2nd fraction, since 21 × 40 = 840,
2/21 = 2 × 40/21 × 40 = 80/840 - Subtract the two like fractions:
147/840 - 80/840 = 147 - 80/840 = 67/840
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/40-2/21 7/40-4/21 7/80-2/21 7/40-2/42 21/40-2/21 7/40-6/21 7/40-2/63 35/40-2/21 7/40-10/21 49/40-2/21 7/40-14/21