Add 42/84 and 45/20
1st number: 42/84, 2nd number: 2 5/20
42/84 + 45/20 is 11/4.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 84 × 5 = 420,
42/84 = 42 × 5/84 × 5 = 210/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
45/20 = 45 × 21/20 × 21 = 945/420 - Add the two like fractions:
210/420 + 945/420 = 210 + 945/420 = 1155/420 - 1155/420 simplified gives 11/4
- So, 42/84 + 45/20 = 11/4
In mixed form: 23/4
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/84+90/20 42/84+45/40 42/84+45/60