Subtract 28/32 from 21/30
21/30 - 28/32 is -7/40.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 32 is 480
Next, find the equivalent fraction of both fractional numbers with denominator 480 - For the 1st fraction, since 30 × 16 = 480,
21/30 = 21 × 16/30 × 16 = 336/480 - Likewise, for the 2nd fraction, since 32 × 15 = 480,
28/32 = 28 × 15/32 × 15 = 420/480 - Subtract the two like fractions:
336/480 - 420/480 = 336 - 420/480 = -84/480 - After reducing the fraction, the answer is -7/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/30-28/32 21/30-56/32 21/60-28/32 21/30-28/64 63/30-28/32 21/30-84/32 21/90-28/32 21/30-28/96