Add 7/15 and 1/21
7/15 + 1/21 is 18/35.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 15 and 21 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 15 × 7 = 105,
7/15 = 7 × 7/15 × 7 = 49/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
1/21 = 1 × 5/21 × 5 = 5/105 - Add the two like fractions:
49/105 + 5/105 = 49 + 5/105 = 54/105 - 54/105 simplified gives 18/35
- So, 7/15 + 1/21 = 18/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/15+1/21 7/15+2/21 7/30+1/21 7/15+1/42 21/15+1/21 7/15+3/21 7/45+1/21 7/15+1/63 35/15+1/21 7/15+5/21 7/75+1/21 49/15+1/21 7/15+7/21