Add 40/8 and 15/21
1st number: 5 0/8, 2nd number: 15/21
40/8 + 15/21 is 40/7.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 21 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 8 × 21 = 168,
40/8 = 40 × 21/8 × 21 = 840/168 - Likewise, for the 2nd fraction, since 21 × 8 = 168,
15/21 = 15 × 8/21 × 8 = 120/168 - Add the two like fractions:
840/168 + 120/168 = 840 + 120/168 = 960/168 - 960/168 simplified gives 40/7
- So, 40/8 + 15/21 = 40/7
In mixed form: 55/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 80/8+15/21 40/8+30/21 40/16+15/21 40/8+15/42 40/8+45/21 40/24+15/21 40/8+15/63 40/8+75/21 40/56+15/21