Add 28/21 and 15/24, Solve 1 7/21 + 15/24 as a fraction

Add 28/21 and 15/24

1^st number: 1 7/21, 2^nd number: 15/24

28/21 + 15/24 is 47/24.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 24 is 168

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 21 × 8 = 168,
28/21 = 28 × 8/21 × 8 = 224/168
Likewise, for the 2nd fraction, since 24 × 7 = 168,
15/24 = 15 × 7/24 × 7 = 105/168
Add the two like fractions:
224/168 + 105/168 = 224 + 105/168 = 329/168
329/168 simplified gives 47/24
So, 28/21 + 15/24 = 47/24
In mixed form: 123/24

MathStep (Works offline)

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