Add 5/21 and 42/54
5/21 + 42/54 is 64/63.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 54 is 378
Next, find the equivalent fraction of both fractional numbers with denominator 378 - For the 1st fraction, since 21 × 18 = 378,
5/21 = 5 × 18/21 × 18 = 90/378 - Likewise, for the 2nd fraction, since 54 × 7 = 378,
42/54 = 42 × 7/54 × 7 = 294/378 - Add the two like fractions:
90/378 + 294/378 = 90 + 294/378 = 384/378 - 384/378 simplified gives 64/63
- So, 5/21 + 42/54 = 64/63
In mixed form: 11/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 10/21+42/54 5/21+84/54 5/42+42/54 15/21+42/54 5/63+42/54 25/21+42/54 35/21+42/54