Add 12/21 and 7/40
12/21 + 7/40 is 209/280.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 21 × 40 = 840,
12/21 = 12 × 40/21 × 40 = 480/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
7/40 = 7 × 21/40 × 21 = 147/840 - Add the two like fractions:
480/840 + 147/840 = 480 + 147/840 = 627/840 - 627/840 simplified gives 209/280
- So, 12/21 + 7/40 = 209/280
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/21+7/40 12/21+14/40 12/42+7/40 12/21+7/80 36/21+7/40 12/21+21/40 12/63+7/40 60/21+7/40 12/21+35/40 84/21+7/40 12/21+49/40