Subtract 24/18 from 21/45
1st number: 21/45, 2nd number: 1 6/18
21/45 - 24/18 is -13/15.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 45 and 18 is 90
Next, find the equivalent fraction of both fractional numbers with denominator 90 - For the 1st fraction, since 45 × 2 = 90,
21/45 = 21 × 2/45 × 2 = 42/90 - Likewise, for the 2nd fraction, since 18 × 5 = 90,
24/18 = 24 × 5/18 × 5 = 120/90 - Subtract the two like fractions:
42/90 - 120/90 = 42 - 120/90 = -78/90 - After reducing the fraction, the answer is -13/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/45-24/18 21/45-48/18 21/90-24/18 21/45-24/36 63/45-24/18 21/45-72/18 21/45-24/54 21/45-24/90