Add 24/28 and 70/21, Solve 24/28 + 3 7/21 as a fraction

Add 24/28 and 70/21

1^st number: 24/28, 2^nd number: 3 7/21

24/28 + 70/21 is 88/21.

Find the least common denominator or LCM of the two denominators:
LCM of 28 and 21 is 84

Next, find the equivalent fraction of both fractional numbers with denominator 84
For the 1st fraction, since 28 × 3 = 84,
24/28 = 24 × 3/28 × 3 = 72/84
Likewise, for the 2nd fraction, since 21 × 4 = 84,
70/21 = 70 × 4/21 × 4 = 280/84
Add the two like fractions:
72/84 + 280/84 = 72 + 280/84 = 352/84
352/84 simplified gives 88/21
So, 24/28 + 70/21 = 88/21
In mixed form: 44/21

MathStep (Works offline)

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