Add 21/42 and 36/45
21/42 + 36/45 is 13/10.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 45 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 42 × 15 = 630,
21/42 = 21 × 15/42 × 15 = 315/630 - Likewise, for the 2nd fraction, since 45 × 14 = 630,
36/45 = 36 × 14/45 × 14 = 504/630 - Add the two like fractions:
315/630 + 504/630 = 315 + 504/630 = 819/630 - 819/630 simplified gives 13/10
- So, 21/42 + 36/45 = 13/10
In mixed form: 13/10
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/42+72/45 21/84+36/45 21/42+36/90 63/42+36/45