Subtract 7/21 from 18/40
18/40 - 7/21 is 7/60.
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,
18/40 = 18 × 21/40 × 21 = 378/840 - Likewise, for the 2nd fraction, since 21 × 40 = 840,
7/21 = 7 × 40/21 × 40 = 280/840 - Subtract the two like fractions:
378/840 - 280/840 = 378 - 280/840 = 98/840 - After reducing the fraction, the answer is 7/60
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/40-7/21 18/40-14/21 18/80-7/21 18/40-7/42 54/40-7/21 18/40-7/63 90/40-7/21 18/40-35/21 18/40-49/21