Subtract 70/18 from 81/42
1st number: 1 39/42, 2nd number: 3 16/18
81/42 - 70/18 is -247/126.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 42 × 3 = 126,
81/42 = 81 × 3/42 × 3 = 243/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
70/18 = 70 × 7/18 × 7 = 490/126 - Subtract the two like fractions:
243/126 - 490/126 = 243 - 490/126 = -247/126
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/84-70/18 81/42-70/36 81/42-70/54 81/42-70/90