Add 90/21 and 90/72
1st number: 4 6/21, 2nd number: 1 18/72
90/21 + 90/72 is 155/28.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 72 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 21 × 24 = 504,
90/21 = 90 × 24/21 × 24 = 2160/504 - Likewise, for the 2nd fraction, since 72 × 7 = 504,
90/72 = 90 × 7/72 × 7 = 630/504 - Add the two like fractions:
2160/504 + 630/504 = 2160 + 630/504 = 2790/504 - 2790/504 simplified gives 155/28
- So, 90/21 + 90/72 = 155/28
In mixed form: 515/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/42+90/72 90/63+90/72