Subtract 16/21 from 3/18
3/18 - 16/21 is -25/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 21 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 18 × 7 = 126,
3/18 = 3 × 7/18 × 7 = 21/126 - Likewise, for the 2nd fraction, since 21 × 6 = 126,
16/21 = 16 × 6/21 × 6 = 96/126 - Subtract the two like fractions:
21/126 - 96/126 = 21 - 96/126 = -75/126 - After reducing the fraction, the answer is -25/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/18-16/21 3/18-32/21 3/36-16/21 3/18-16/42 9/18-16/21 3/18-48/21 3/54-16/21 3/18-16/63 15/18-16/21 3/18-80/21 3/90-16/21 21/18-16/21