Subtract 10/8 from 42/15, Solve 2 12/15

Subtract 10/8 from 42/15

1^st number: 2 12/15, 2^nd number: 1 2/8

42/15 - 10/8 is 31/20.

Find the least common denominator or LCM of the two denominators:
LCM of 15 and 8 is 120

Next, find the equivalent fraction of both fractional numbers with denominator 120
For the 1st fraction, since 15 × 8 = 120,
42/15 = 42 × 8/15 × 8 = 336/120
Likewise, for the 2nd fraction, since 8 × 15 = 120,
10/8 = 10 × 15/8 × 15 = 150/120
Subtract the two like fractions:
336/120 - 150/120 = 336 - 150/120 = 186/120
After reducing the fraction, the answer is 31/20
In mixed form: 111/20

MathStep (Works offline)

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