Subtract 3/9 from 72/42, Solve 1 30/42

Subtract 3/9 from 72/42

1^st number: 1 30/42, 2^nd number: 3/9

72/42 - 3/9 is 29/21.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 9 is 126

Next, find the equivalent fraction of both fractional numbers with denominator 126
For the 1st fraction, since 42 × 3 = 126,
72/42 = 72 × 3/42 × 3 = 216/126
Likewise, for the 2nd fraction, since 9 × 14 = 126,
3/9 = 3 × 14/9 × 14 = 42/126
Subtract the two like fractions:
216/126 - 42/126 = 216 - 42/126 = 174/126
After reducing the fraction, the answer is 29/21
In mixed form: 18/21

MathStep (Works offline)

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