Subtract 45/40 from 5/42, Solve 5/42

Subtract 45/40 from 5/42

1^st number: 5/42, 2^nd number: 1 5/40

5/42 - 45/40 is -169/168.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 40 is 840

Next, find the equivalent fraction of both fractional numbers with denominator 840
For the 1st fraction, since 42 × 20 = 840,
5/42 = 5 × 20/42 × 20 = 100/840
Likewise, for the 2nd fraction, since 40 × 21 = 840,
45/40 = 45 × 21/40 × 21 = 945/840
Subtract the two like fractions:
100/840 - 945/840 = 100 - 945/840 = -845/840
After reducing the fraction, the answer is -169/168

MathStep (Works offline)

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