Subtract 42/84 from 72/20
1st number: 3 12/20, 2nd number: 42/84
72/20 - 42/84 is 31/10.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 84 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 20 × 21 = 420,
72/20 = 72 × 21/20 × 21 = 1512/420 - Likewise, for the 2nd fraction, since 84 × 5 = 420,
42/84 = 42 × 5/84 × 5 = 210/420 - Subtract the two like fractions:
1512/420 - 210/420 = 1512 - 210/420 = 1302/420 - After reducing the fraction, the answer is 31/10
- In mixed form: 31/10
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/40-42/84 72/60-42/84