Add 1/21 and 72/90
1/21 + 72/90 is 89/105.
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,
1/21 = 1 × 30/21 × 30 = 30/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
72/90 = 72 × 7/90 × 7 = 504/630 - Add the two like fractions:
30/630 + 504/630 = 30 + 504/630 = 534/630 - 534/630 simplified gives 89/105
- So, 1/21 + 72/90 = 89/105
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/21+72/90 1/42+72/90 3/21+72/90 1/63+72/90 5/21+72/90 7/21+72/90