Add 20/70 and 9/21
20/70 + 9/21 is 5/7.
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,
20/70 = 20 × 3/70 × 3 = 60/210 - Likewise, for the 2nd fraction, since 21 × 10 = 210,
9/21 = 9 × 10/21 × 10 = 90/210 - Add the two like fractions:
60/210 + 90/210 = 60 + 90/210 = 150/210 - 150/210 simplified gives 5/7
- So, 20/70 + 9/21 = 5/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/70+9/21 20/70+18/21 20/70+9/42 60/70+9/21 20/70+27/21 20/70+9/63 20/70+45/21 20/70+63/21