Subtract 40/70 from 90/84, Solve 1 6/84

Subtract 40/70 from 90/84

1^st number: 1 6/84, 2^nd number: 40/70

90/84 - 40/70 is 1/2.

Find the least common denominator or LCM of the two denominators:
LCM of 84 and 70 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 84 × 5 = 420,
90/84 = 90 × 5/84 × 5 = 450/420
Likewise, for the 2nd fraction, since 70 × 6 = 420,
40/70 = 40 × 6/70 × 6 = 240/420
Subtract the two like fractions:
450/420 - 240/420 = 450 - 240/420 = 210/420
After reducing the fraction, the answer is 1/2

MathStep (Works offline)

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