Subtract 4/42 from 21/5, Solve 4 1/5

Subtract 4/42 from 21/5

1^st number: 4 1/5, 2^nd number: 4/42

21/5 - 4/42 is 431/105.

Find the least common denominator or LCM of the two denominators:
LCM of 5 and 42 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 5 × 42 = 210,
21/5 = 21 × 42/5 × 42 = 882/210
Likewise, for the 2nd fraction, since 42 × 5 = 210,
4/42 = 4 × 5/42 × 5 = 20/210
Subtract the two like fractions:
882/210 - 20/210 = 882 - 20/210 = 862/210
After reducing the fraction, the answer is 431/105
In mixed form: 411/105

MathStep (Works offline)

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