Subtract 9/7 from 42/45, Solve 42/45

Subtract 9/7 from 42/45

1^st number: 42/45, 2^nd number: 1 2/7

42/45 - 9/7 is -37/105.

Find the least common denominator or LCM of the two denominators:
LCM of 45 and 7 is 315

Next, find the equivalent fraction of both fractional numbers with denominator 315
For the 1st fraction, since 45 × 7 = 315,
42/45 = 42 × 7/45 × 7 = 294/315
Likewise, for the 2nd fraction, since 7 × 45 = 315,
9/7 = 9 × 45/7 × 45 = 405/315
Subtract the two like fractions:
294/315 - 405/315 = 294 - 405/315 = -111/315
After reducing the fraction, the answer is -37/105

MathStep (Works offline)

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