Subtract 21/40 from 30/4
1st number: 7 2/4, 2nd number: 21/40
30/4 - 21/40 is 279/40.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 4 and 40 is 40
Next, find the equivalent fraction of both fractional numbers with denominator 40 - For the 1st fraction, since 4 × 10 = 40,
30/4 = 30 × 10/4 × 10 = 300/40 - Likewise, for the 2nd fraction, since 40 × 1 = 40,
21/40 = 21 × 1/40 × 1 = 21/40 - Subtract the two like fractions:
300/40 - 21/40 = 300 - 21/40 = 279/40 - In mixed form: 639/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/4-21/40 30/4-42/40 30/8-21/40 30/4-21/80 90/4-21/40 30/4-63/40 30/12-21/40 30/20-21/40 30/28-21/40