Add 81/42 and 1/40, Solve 1 39/42 + 1/40 as a fraction

Add 81/42 and 1/40

1^st number: 1 39/42, 2^nd number: 1/40

81/42 + 1/40 is 547/280.

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,
81/42 = 81 × 20/42 × 20 = 1620/840
Likewise, for the 2nd fraction, since 40 × 21 = 840,
1/40 = 1 × 21/40 × 21 = 21/840
Add the two like fractions:
1620/840 + 21/840 = 1620 + 21/840 = 1641/840
1641/840 simplified gives 547/280
So, 81/42 + 1/40 = 547/280
In mixed form: 1267/280

MathStep (Works offline)

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