Add 21/80 and 63/10, Solve 21/80 + 6 3/10 as a fraction

Add 21/80 and 63/10

1^st number: 21/80, 2^nd number: 6 3/10

21/80 + 63/10 is 105/16.

Find the least common denominator or LCM of the two denominators:
LCM of 80 and 10 is 80

Next, find the equivalent fraction of both fractional numbers with denominator 80
For the 1st fraction, since 80 × 1 = 80,
21/80 = 21 × 1/80 × 1 = 21/80
Likewise, for the 2nd fraction, since 10 × 8 = 80,
63/10 = 63 × 8/10 × 8 = 504/80
Add the two like fractions:
21/80 + 504/80 = 21 + 504/80 = 525/80
525/80 simplified gives 105/16
So, 21/80 + 63/10 = 105/16
In mixed form: 69/16

MathStep (Works offline)

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