Subtract 21/40 from 30/42
30/42 - 21/40 is 53/280.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 42 × 20 = 840,
30/42 = 30 × 20/42 × 20 = 600/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
21/40 = 21 × 21/40 × 21 = 441/840 - Subtract the two like fractions:
600/840 - 441/840 = 600 - 441/840 = 159/840 - After reducing the fraction, the answer is 53/280
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/42-21/40 30/42-42/40 30/84-21/40 30/42-21/80 90/42-21/40 30/42-63/40