Add 21/70 and 45/56
21/70 + 45/56 is 309/280.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 56 is 280
Next, find the equivalent fraction of both fractional numbers with denominator 280 - For the 1st fraction, since 70 × 4 = 280,
21/70 = 21 × 4/70 × 4 = 84/280 - Likewise, for the 2nd fraction, since 56 × 5 = 280,
45/56 = 45 × 5/56 × 5 = 225/280 - Add the two like fractions:
84/280 + 225/280 = 84 + 225/280 = 309/280 - So, 21/70 + 45/56 = 309/280
In mixed form: 129/280
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/70+45/56 21/70+90/56 63/70+45/56