Subtract 72/40 from 40/42
1st number: 40/42, 2nd number: 1 32/40
40/42 - 72/40 is -89/105.
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,
40/42 = 40 × 20/42 × 20 = 800/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
72/40 = 72 × 21/40 × 21 = 1512/840 - Subtract the two like fractions:
800/840 - 1512/840 = 800 - 1512/840 = -712/840 - After reducing the fraction, the answer is -89/105
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 80/42-72/40 40/84-72/40 40/42-72/80