Add 81/42 and 20/8
1st number: 1 39/42, 2nd number: 2 4/8
81/42 + 20/8 is 31/7.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 8 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 42 × 4 = 168,
81/42 = 81 × 4/42 × 4 = 324/168 - Likewise, for the 2nd fraction, since 8 × 21 = 168,
20/8 = 20 × 21/8 × 21 = 420/168 - Add the two like fractions:
324/168 + 420/168 = 324 + 420/168 = 744/168 - 744/168 simplified gives 31/7
- So, 81/42 + 20/8 = 31/7
In mixed form: 43/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/42+40/8 81/84+20/8 81/42+20/16 81/42+60/8 81/42+20/24 81/42+20/40 81/42+20/56