Add 21/30 and 7/40
21/30 + 7/40 is 7/8.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 40 is 120
Next, find the equivalent fraction of both fractional numbers with denominator 120 - For the 1st fraction, since 30 × 4 = 120,
21/30 = 21 × 4/30 × 4 = 84/120 - Likewise, for the 2nd fraction, since 40 × 3 = 120,
7/40 = 7 × 3/40 × 3 = 21/120 - Add the two like fractions:
84/120 + 21/120 = 84 + 21/120 = 105/120 - 105/120 simplified gives 7/8
- So, 21/30 + 7/40 = 7/8
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/30+7/40 21/30+14/40 21/60+7/40 21/30+7/80 63/30+7/40 21/30+21/40 21/90+7/40 21/30+35/40 21/30+49/40