Add 12/40 and 28/21
1st number: 12/40, 2nd number: 1 7/21
12/40 + 28/21 is 49/30.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 21 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 40 × 21 = 840,
12/40 = 12 × 21/40 × 21 = 252/840 - Likewise, for the 2nd fraction, since 21 × 40 = 840,
28/21 = 28 × 40/21 × 40 = 1120/840 - Add the two like fractions:
252/840 + 1120/840 = 252 + 1120/840 = 1372/840 - 1372/840 simplified gives 49/30
- So, 12/40 + 28/21 = 49/30
In mixed form: 119/30
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/40+28/21 12/40+56/21 12/80+28/21 12/40+28/42 36/40+28/21 12/40+84/21 12/40+28/63 60/40+28/21 84/40+28/21