Add 5/21 and 70/90
5/21 + 70/90 is 64/63.
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,
5/21 = 5 × 30/21 × 30 = 150/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
70/90 = 70 × 7/90 × 7 = 490/630 - Add the two like fractions:
150/630 + 490/630 = 150 + 490/630 = 640/630 - 640/630 simplified gives 64/63
- So, 5/21 + 70/90 = 64/63
In mixed form: 11/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 10/21+70/90 5/42+70/90 15/21+70/90 5/63+70/90 25/21+70/90 35/21+70/90