Subtract 21/12 from 30/40
1st number: 30/40, 2nd number: 1 9/12
30/40 - 21/12 is -1/1.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 12 is 120
Next, find the equivalent fraction of both fractional numbers with denominator 120 - For the 1st fraction, since 40 × 3 = 120,
30/40 = 30 × 3/40 × 3 = 90/120 - Likewise, for the 2nd fraction, since 12 × 10 = 120,
21/12 = 21 × 10/12 × 10 = 210/120 - Subtract the two like fractions:
90/120 - 210/120 = 90 - 210/120 = -120/120 - After reducing the fraction, the answer is -1/1
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/40-21/12 30/40-42/12 30/80-21/12 30/40-21/24 90/40-21/12 30/40-63/12 30/40-21/36 30/40-21/60 30/40-21/84