Add 21/40 and 3/7
21/40 + 3/7 is 267/280.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 7 is 280
Next, find the equivalent fraction of both fractional numbers with denominator 280 - For the 1st fraction, since 40 × 7 = 280,
21/40 = 21 × 7/40 × 7 = 147/280 - Likewise, for the 2nd fraction, since 7 × 40 = 280,
3/7 = 3 × 40/7 × 40 = 120/280 - Add the two like fractions:
147/280 + 120/280 = 147 + 120/280 = 267/280 - So, 21/40 + 3/7 = 267/280
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/40+3/7 21/40+6/7 21/80+3/7 21/40+3/14 63/40+3/7 21/40+9/7 21/40+3/21 21/40+15/7 21/40+3/35 21/40+21/7 21/40+3/49