Subtract 40/12 from 45/21
1st number: 2 3/21, 2nd number: 3 4/12
45/21 - 40/12 is -25/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 12 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
45/21 = 45 × 4/21 × 4 = 180/84 - Likewise, for the 2nd fraction, since 12 × 7 = 84,
40/12 = 40 × 7/12 × 7 = 280/84 - Subtract the two like fractions:
180/84 - 280/84 = 180 - 280/84 = -100/84 - After reducing the fraction, the answer is -25/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/21-40/12 45/21-80/12 45/42-40/12 45/21-40/24 45/63-40/12 45/21-40/36 45/21-40/60 45/21-40/84