Add 21/28 and 12/40
21/28 + 12/40 is 21/20.
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,
12/40 = 12 × 7/40 × 7 = 84/280 - Add the two like fractions:
210/280 + 84/280 = 210 + 84/280 = 294/280 - 294/280 simplified gives 21/20
- So, 21/28 + 12/40 = 21/20
In mixed form: 11/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28+12/40 21/28+24/40 21/56+12/40 21/28+12/80 63/28+12/40 21/28+36/40 21/84+12/40 21/28+60/40 21/28+84/40