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

Subtract 1/40 from 90/84

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

90/84 - 1/40 is 293/280.

Find the least common denominator or LCM of the two denominators:
LCM of 84 and 40 is 840

Next, find the equivalent fraction of both fractional numbers with denominator 840
For the 1st fraction, since 84 × 10 = 840,
90/84 = 90 × 10/84 × 10 = 900/840
Likewise, for the 2nd fraction, since 40 × 21 = 840,
1/40 = 1 × 21/40 × 21 = 21/840
Subtract the two like fractions:
900/840 - 21/840 = 900 - 21/840 = 879/840
After reducing the fraction, the answer is 293/280
In mixed form: 113/280

MathStep (Works offline)

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