Subtract 70/40 from 72/42
1st number: 1 30/42, 2nd number: 1 30/40
72/42 - 70/40 is -1/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 42 × 20 = 840,
72/42 = 72 × 20/42 × 20 = 1440/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
70/40 = 70 × 21/40 × 21 = 1470/840 - Subtract the two like fractions:
1440/840 - 1470/840 = 1440 - 1470/840 = -30/840 - After reducing the fraction, the answer is -1/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/84-70/40 72/42-70/80