Subtract 20/42 from 20/30
20/30 - 20/42 is 4/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 42 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 30 × 7 = 210,
20/30 = 20 × 7/30 × 7 = 140/210 - Likewise, for the 2nd fraction, since 42 × 5 = 210,
20/42 = 20 × 5/42 × 5 = 100/210 - Subtract the two like fractions:
140/210 - 100/210 = 140 - 100/210 = 40/210 - After reducing the fraction, the answer is 4/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/30-20/42 20/30-40/42 20/60-20/42 20/30-20/84 60/30-20/42 20/30-60/42 20/90-20/42