Add 70/21 and 72/90
1st number: 3 7/21, 2nd number: 72/90
70/21 + 72/90 is 62/15.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 21 × 30 = 630,
70/21 = 70 × 30/21 × 30 = 2100/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
72/90 = 72 × 7/90 × 7 = 504/630 - Add the two like fractions:
2100/630 + 504/630 = 2100 + 504/630 = 2604/630 - 2604/630 simplified gives 62/15
- So, 70/21 + 72/90 = 62/15
In mixed form: 42/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 70/42+72/90 70/63+72/90