Add 54/84 and 20/21
54/84 + 20/21 is 67/42.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 84 × 1 = 84,
54/84 = 54 × 1/84 × 1 = 54/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
20/21 = 20 × 4/21 × 4 = 80/84 - Add the two like fractions:
54/84 + 80/84 = 54 + 80/84 = 134/84 - 134/84 simplified gives 67/42
- So, 54/84 + 20/21 = 67/42
In mixed form: 125/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 54/84+40/21 54/84+20/42 54/84+60/21 54/84+20/63