Subtract 80/42 from 20/70
1st number: 20/70, 2nd number: 1 38/42
20/70 - 80/42 is -34/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 42 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 70 × 3 = 210,
20/70 = 20 × 3/70 × 3 = 60/210 - Likewise, for the 2nd fraction, since 42 × 5 = 210,
80/42 = 80 × 5/42 × 5 = 400/210 - Subtract the two like fractions:
60/210 - 400/210 = 60 - 400/210 = -340/210 - After reducing the fraction, the answer is -34/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/70-80/42 20/70-80/84 60/70-80/42