Add 21/28 and 12/30
21/28 + 12/30 is 23/20.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 30 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 28 × 15 = 420,
21/28 = 21 × 15/28 × 15 = 315/420 - Likewise, for the 2nd fraction, since 30 × 14 = 420,
12/30 = 12 × 14/30 × 14 = 168/420 - Add the two like fractions:
315/420 + 168/420 = 315 + 168/420 = 483/420 - 483/420 simplified gives 23/20
- So, 21/28 + 12/30 = 23/20
In mixed form: 13/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28+12/30 21/28+24/30 21/56+12/30 21/28+12/60 63/28+12/30 21/28+36/30 21/84+12/30 21/28+12/90 21/28+60/30 21/28+84/30