Subtract 8/40 from 21/12
1st number: 1 9/12, 2nd number: 8/40
21/12 - 8/40 is 31/20.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 40 is 120
Next, find the equivalent fraction of both fractional numbers with denominator 120 - For the 1st fraction, since 12 × 10 = 120,
21/12 = 21 × 10/12 × 10 = 210/120 - Likewise, for the 2nd fraction, since 40 × 3 = 120,
8/40 = 8 × 3/40 × 3 = 24/120 - Subtract the two like fractions:
210/120 - 24/120 = 210 - 24/120 = 186/120 - After reducing the fraction, the answer is 31/20
- In mixed form: 111/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/12-8/40 21/12-16/40 21/24-8/40 21/12-8/80 63/12-8/40 21/12-24/40 21/36-8/40 21/60-8/40 21/12-56/40 21/84-8/40