Add 84/8 and 3/21, Solve 10 4/8 + 3/21 as a fraction

Add 84/8 and 3/21

1^st number: 10 4/8, 2^nd number: 3/21

84/8 + 3/21 is 149/14.

Find the least common denominator or LCM of the two denominators:
LCM of 8 and 21 is 168

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 8 × 21 = 168,
84/8 = 84 × 21/8 × 21 = 1764/168
Likewise, for the 2nd fraction, since 21 × 8 = 168,
3/21 = 3 × 8/21 × 8 = 24/168
Add the two like fractions:
1764/168 + 24/168 = 1764 + 24/168 = 1788/168
1788/168 simplified gives 149/14
So, 84/8 + 3/21 = 149/14
In mixed form: 109/14

MathStep (Works offline)

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