Subtract 3/42 from 21/18
1st number: 1 3/18, 2nd number: 3/42
21/18 - 3/42 is 23/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 42 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 18 × 7 = 126,
21/18 = 21 × 7/18 × 7 = 147/126 - Likewise, for the 2nd fraction, since 42 × 3 = 126,
3/42 = 3 × 3/42 × 3 = 9/126 - Subtract the two like fractions:
147/126 - 9/126 = 147 - 9/126 = 138/126 - After reducing the fraction, the answer is 23/21
- In mixed form: 12/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/18-3/42 21/18-6/42 21/36-3/42 21/18-3/84 63/18-3/42 21/18-9/42 21/54-3/42 21/18-15/42 21/90-3/42 21/18-21/42