Add 21/30 and 20/28
21/30 + 20/28 is 99/70.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 28 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 30 × 14 = 420,
21/30 = 21 × 14/30 × 14 = 294/420 - Likewise, for the 2nd fraction, since 28 × 15 = 420,
20/28 = 20 × 15/28 × 15 = 300/420 - Add the two like fractions:
294/420 + 300/420 = 294 + 300/420 = 594/420 - 594/420 simplified gives 99/70
- So, 21/30 + 20/28 = 99/70
In mixed form: 129/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/30+20/28 21/30+40/28 21/60+20/28 21/30+20/56 63/30+20/28 21/30+60/28 21/90+20/28 21/30+20/84