Subtract 5/21 from 3/40
3/40 - 5/21 is -137/840.
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,
3/40 = 3 × 21/40 × 21 = 63/840 - Likewise, for the 2nd fraction, since 21 × 40 = 840,
5/21 = 5 × 40/21 × 40 = 200/840 - Subtract the two like fractions:
63/840 - 200/840 = 63 - 200/840 = -137/840
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/40-5/21 3/40-10/21 3/80-5/21 3/40-5/42 9/40-5/21 3/40-15/21 3/40-5/63 15/40-5/21 3/40-25/21 21/40-5/21 3/40-35/21