Add 21/70 and 21/84
21/70 + 21/84 is 11/20.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 84 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 70 × 6 = 420,
21/70 = 21 × 6/70 × 6 = 126/420 - Likewise, for the 2nd fraction, since 84 × 5 = 420,
21/84 = 21 × 5/84 × 5 = 105/420 - Add the two like fractions:
126/420 + 105/420 = 126 + 105/420 = 231/420 - 231/420 simplified gives 11/20
- So, 21/70 + 21/84 = 11/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/70+21/84 21/70+42/84 63/70+21/84 21/70+63/84