Add 21/28 and 18/40
21/28 + 18/40 is 6/5.
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,
18/40 = 18 × 7/40 × 7 = 126/280 - Add the two like fractions:
210/280 + 126/280 = 210 + 126/280 = 336/280 - 336/280 simplified gives 6/5
- So, 21/28 + 18/40 = 6/5
In mixed form: 11/5
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28+18/40 21/28+36/40 21/56+18/40 21/28+18/80 63/28+18/40 21/28+54/40 21/84+18/40 21/28+90/40