Subtract 21/45 from 12/30
12/30 - 21/45 is -1/15.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 45 is 90
Next, find the equivalent fraction of both fractional numbers with denominator 90 - For the 1st fraction, since 30 × 3 = 90,
12/30 = 12 × 3/30 × 3 = 36/90 - Likewise, for the 2nd fraction, since 45 × 2 = 90,
21/45 = 21 × 2/45 × 2 = 42/90 - Subtract the two like fractions:
36/90 - 42/90 = 36 - 42/90 = -6/90 - After reducing the fraction, the answer is -1/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/30-21/45 12/30-42/45 12/60-21/45 12/30-21/90 36/30-21/45 12/30-63/45 12/90-21/45 60/30-21/45 84/30-21/45