Add 21/30 and 42/84
21/30 + 42/84 is 6/5.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 84 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 30 × 14 = 420,
21/30 = 21 × 14/30 × 14 = 294/420 - Likewise, for the 2nd fraction, since 84 × 5 = 420,
42/84 = 42 × 5/84 × 5 = 210/420 - Add the two like fractions:
294/420 + 210/420 = 294 + 210/420 = 504/420 - 504/420 simplified gives 6/5
- So, 21/30 + 42/84 = 6/5
In mixed form: 11/5
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/30+42/84 21/60+42/84 63/30+42/84 21/90+42/84