Subtract 90/30 from 20/42
1st number: 20/42, 2nd number: 3 0/30
20/42 - 90/30 is -53/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 30 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 42 × 5 = 210,
20/42 = 20 × 5/42 × 5 = 100/210 - Likewise, for the 2nd fraction, since 30 × 7 = 210,
90/30 = 90 × 7/30 × 7 = 630/210 - Subtract the two like fractions:
100/210 - 630/210 = 100 - 630/210 = -530/210 - After reducing the fraction, the answer is -53/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/42-90/30 20/84-90/30 20/42-90/60 60/42-90/30