Add 21/63 and 28/70
21/63 + 28/70 is 11/15.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 63 and 70 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 63 × 10 = 630,
21/63 = 21 × 10/63 × 10 = 210/630 - Likewise, for the 2nd fraction, since 70 × 9 = 630,
28/70 = 28 × 9/70 × 9 = 252/630 - Add the two like fractions:
210/630 + 252/630 = 210 + 252/630 = 462/630 - 462/630 simplified gives 11/15
- So, 21/63 + 28/70 = 11/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/63+28/70 21/63+56/70 21/63+84/70