Add 63/16 and 12/21, Solve 3 15/16 + 12/21 as a fraction

Add 63/16 and 12/21

1^st number: 3 15/16, 2^nd number: 12/21

63/16 + 12/21 is 505/112.

Find the least common denominator or LCM of the two denominators:
LCM of 16 and 21 is 336

Next, find the equivalent fraction of both fractional numbers with denominator 336
For the 1st fraction, since 16 × 21 = 336,
63/16 = 63 × 21/16 × 21 = 1323/336
Likewise, for the 2nd fraction, since 21 × 16 = 336,
12/21 = 12 × 16/21 × 16 = 192/336
Add the two like fractions:
1323/336 + 192/336 = 1323 + 192/336 = 1515/336
1515/336 simplified gives 505/112
So, 63/16 + 12/21 = 505/112
In mixed form: 457/112

MathStep (Works offline)

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