Add 45/70 and 12/21
45/70 + 12/21 is 17/14.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 21 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 70 × 3 = 210,
45/70 = 45 × 3/70 × 3 = 135/210 - Likewise, for the 2nd fraction, since 21 × 10 = 210,
12/21 = 12 × 10/21 × 10 = 120/210 - Add the two like fractions:
135/210 + 120/210 = 135 + 120/210 = 255/210 - 255/210 simplified gives 17/14
- So, 45/70 + 12/21 = 17/14
In mixed form: 13/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/70+12/21 45/70+24/21 45/70+12/42 45/70+36/21 45/70+12/63 45/70+60/21 45/70+84/21