Add 21/40 and 3/15
21/40 + 3/15 is 29/40.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 15 is 120
Next, find the equivalent fraction of both fractional numbers with denominator 120 - For the 1st fraction, since 40 × 3 = 120,
21/40 = 21 × 3/40 × 3 = 63/120 - Likewise, for the 2nd fraction, since 15 × 8 = 120,
3/15 = 3 × 8/15 × 8 = 24/120 - Add the two like fractions:
63/120 + 24/120 = 63 + 24/120 = 87/120 - 87/120 simplified gives 29/40
- So, 21/40 + 3/15 = 29/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/40+3/15 21/40+6/15 21/80+3/15 21/40+3/30 63/40+3/15 21/40+9/15 21/40+3/45 21/40+3/75 21/40+21/15