Add 12/42 and 21/30
12/42 + 21/30 is 69/70.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 30 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 42 × 5 = 210,
12/42 = 12 × 5/42 × 5 = 60/210 - Likewise, for the 2nd fraction, since 30 × 7 = 210,
21/30 = 21 × 7/30 × 7 = 147/210 - Add the two like fractions:
60/210 + 147/210 = 60 + 147/210 = 207/210 - 207/210 simplified gives 69/70
- So, 12/42 + 21/30 = 69/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/42+21/30 12/42+42/30 12/84+21/30 12/42+21/60 36/42+21/30 12/42+63/30 12/42+21/90 60/42+21/30 84/42+21/30