Add 15/8 and 21/63, Solve 1 7/8 + 21/63 as a fraction

Add 15/8 and 21/63

1^st number: 1 7/8, 2^nd number: 21/63

15/8 + 21/63 is 53/24.

Find the least common denominator or LCM of the two denominators:
LCM of 8 and 63 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 8 × 63 = 504,
15/8 = 15 × 63/8 × 63 = 945/504
Likewise, for the 2nd fraction, since 63 × 8 = 504,
21/63 = 21 × 8/63 × 8 = 168/504
Add the two like fractions:
945/504 + 168/504 = 945 + 168/504 = 1113/504
1113/504 simplified gives 53/24
So, 15/8 + 21/63 = 53/24
In mixed form: 25/24

MathStep (Works offline)

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