Subtract 18/42 from 3/72
3/72 - 18/42 is -65/168.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 42 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 72 × 7 = 504,
3/72 = 3 × 7/72 × 7 = 21/504 - Likewise, for the 2nd fraction, since 42 × 12 = 504,
18/42 = 18 × 12/42 × 12 = 216/504 - Subtract the two like fractions:
21/504 - 216/504 = 21 - 216/504 = -195/504 - After reducing the fraction, the answer is -65/168
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/72-18/42 3/72-36/42 3/72-18/84 9/72-18/42 3/72-54/42 15/72-18/42 3/72-90/42 21/72-18/42