Add 12/45 and 70/21
1st number: 12/45, 2nd number: 3 7/21
12/45 + 70/21 is 18/5.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 45 and 21 is 315
Next, find the equivalent fraction of both fractional numbers with denominator 315 - For the 1st fraction, since 45 × 7 = 315,
12/45 = 12 × 7/45 × 7 = 84/315 - Likewise, for the 2nd fraction, since 21 × 15 = 315,
70/21 = 70 × 15/21 × 15 = 1050/315 - Add the two like fractions:
84/315 + 1050/315 = 84 + 1050/315 = 1134/315 - 1134/315 simplified gives 18/5
- So, 12/45 + 70/21 = 18/5
In mixed form: 33/5
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/45+70/21 12/90+70/21 12/45+70/42 36/45+70/21 12/45+70/63 60/45+70/21 84/45+70/21