Subtract 20/42 from 3/9
3/9 - 20/42 is -1/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 9 and 42 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 9 × 14 = 126,
3/9 = 3 × 14/9 × 14 = 42/126 - Likewise, for the 2nd fraction, since 42 × 3 = 126,
20/42 = 20 × 3/42 × 3 = 60/126 - Subtract the two like fractions:
42/126 - 60/126 = 42 - 60/126 = -18/126 - After reducing the fraction, the answer is -1/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/9-20/42 3/9-40/42 3/18-20/42 3/9-20/84 3/9-60/42 3/27-20/42 15/9-20/42 3/45-20/42 21/9-20/42 3/63-20/42