Add 21/12 and 40/42
1st number: 1 9/12, 2nd number: 40/42
21/12 + 40/42 is 227/84.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 42 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 12 × 7 = 84,
21/12 = 21 × 7/12 × 7 = 147/84 - Likewise, for the 2nd fraction, since 42 × 2 = 84,
40/42 = 40 × 2/42 × 2 = 80/84 - Add the two like fractions:
147/84 + 80/84 = 147 + 80/84 = 227/84 - So, 21/12 + 40/42 = 227/84
In mixed form: 259/84
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/12+40/42 21/12+80/42 21/24+40/42 21/12+40/84 63/12+40/42 21/36+40/42 21/60+40/42 21/84+40/42