Add 21/28 and 30/40
21/28 + 30/40 is 3/2.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 40 is 280
Next, find the equivalent fraction of both fractional numbers with denominator 280 - For the 1st fraction, since 28 × 10 = 280,
21/28 = 21 × 10/28 × 10 = 210/280 - Likewise, for the 2nd fraction, since 40 × 7 = 280,
30/40 = 30 × 7/40 × 7 = 210/280 - Add the two like fractions:
210/280 + 210/280 = 210 + 210/280 = 420/280 - 420/280 simplified gives 3/2
- So, 21/28 + 30/40 = 3/2
In mixed form: 11/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28+30/40 21/28+60/40 21/56+30/40 21/28+30/80 63/28+30/40 21/28+90/40 21/84+30/40