Add 20/24 and 18/21
20/24 + 18/21 is 71/42.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 24 and 21 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 24 × 7 = 168,
20/24 = 20 × 7/24 × 7 = 140/168 - Likewise, for the 2nd fraction, since 21 × 8 = 168,
18/21 = 18 × 8/21 × 8 = 144/168 - Add the two like fractions:
140/168 + 144/168 = 140 + 144/168 = 284/168 - 284/168 simplified gives 71/42
- So, 20/24 + 18/21 = 71/42
In mixed form: 129/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/24+18/21 20/24+36/21 20/48+18/21 20/24+18/42 60/24+18/21 20/24+54/21 20/72+18/21 20/24+18/63 20/24+90/21