Add 15/70 and 81/90
15/70 + 81/90 is 39/35.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 70 × 9 = 630,
15/70 = 15 × 9/70 × 9 = 135/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
81/90 = 81 × 7/90 × 7 = 567/630 - Add the two like fractions:
135/630 + 567/630 = 135 + 567/630 = 702/630 - 702/630 simplified gives 39/35
- So, 15/70 + 81/90 = 39/35
In mixed form: 14/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/70+81/90 45/70+81/90 75/70+81/90