Add 8/20 and 42/21
1st number: 8/20, 2nd number: 2 0/21
8/20 + 42/21 is 12/5.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 21 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 20 × 21 = 420,
8/20 = 8 × 21/20 × 21 = 168/420 - Likewise, for the 2nd fraction, since 21 × 20 = 420,
42/21 = 42 × 20/21 × 20 = 840/420 - Add the two like fractions:
168/420 + 840/420 = 168 + 840/420 = 1008/420 - 1008/420 simplified gives 12/5
- So, 8/20 + 42/21 = 12/5
In mixed form: 22/5
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 16/20+42/21 8/20+84/21 8/40+42/21 24/20+42/21 8/60+42/21 8/20+42/63 40/20+42/21 56/20+42/21