Add 21/8 and 21/84, Solve 2 5/8 + 21/84 as a fraction

Add 21/8 and 21/84

1^st number: 2 5/8, 2^nd number: 21/84

21/8 + 21/84 is 23/8.

Find the least common denominator or LCM of the two denominators:
LCM of 8 and 84 is 168

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 8 × 21 = 168,
21/8 = 21 × 21/8 × 21 = 441/168
Likewise, for the 2nd fraction, since 84 × 2 = 168,
21/84 = 21 × 2/84 × 2 = 42/168
Add the two like fractions:
441/168 + 42/168 = 441 + 42/168 = 483/168
483/168 simplified gives 23/8
So, 21/8 + 21/84 = 23/8
In mixed form: 27/8

MathStep (Works offline)

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