Subtract 21/30 from 40/45
40/45 - 21/30 is 17/90.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 45 and 30 is 90
Next, find the equivalent fraction of both fractional numbers with denominator 90 - For the 1st fraction, since 45 × 2 = 90,
40/45 = 40 × 2/45 × 2 = 80/90 - Likewise, for the 2nd fraction, since 30 × 3 = 90,
21/30 = 21 × 3/30 × 3 = 63/90 - Subtract the two like fractions:
80/90 - 63/90 = 80 - 63/90 = 17/90
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 80/45-21/30 40/45-42/30 40/90-21/30 40/45-21/60 40/45-63/30 40/45-21/90