Subtract 21/5 from 30/4, Solve 7 2/4

Subtract 21/5 from 30/4

1^st number: 7 2/4, 2^nd number: 4 1/5

30/4 - 21/5 is 33/10.

Find the least common denominator or LCM of the two denominators:
LCM of 4 and 5 is 20

Next, find the equivalent fraction of both fractional numbers with denominator 20
For the 1st fraction, since 4 × 5 = 20,
30/4 = 30 × 5/4 × 5 = 150/20
Likewise, for the 2nd fraction, since 5 × 4 = 20,
21/5 = 21 × 4/5 × 4 = 84/20
Subtract the two like fractions:
150/20 - 84/20 = 150 - 84/20 = 66/20
After reducing the fraction, the answer is 33/10
In mixed form: 33/10

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad