Subtract 15/42 from 3/18
3/18 - 15/42 is -4/21.
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,
3/18 = 3 × 7/18 × 7 = 21/126 - Likewise, for the 2nd fraction, since 42 × 3 = 126,
15/42 = 15 × 3/42 × 3 = 45/126 - Subtract the two like fractions:
21/126 - 45/126 = 21 - 45/126 = -24/126 - 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: 6/18-15/42 3/18-30/42 3/36-15/42 3/18-15/84 9/18-15/42 3/18-45/42 3/54-15/42 15/18-15/42 3/18-75/42 3/90-15/42 21/18-15/42