Add 40/30 and 21/84, Solve 1 10/30 + 21/84 as a fraction

Add 40/30 and 21/84

1^st number: 1 10/30, 2^nd number: 21/84

40/30 + 21/84 is 19/12.

Find the least common denominator or LCM of the two denominators:
LCM of 30 and 84 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 30 × 14 = 420,
40/30 = 40 × 14/30 × 14 = 560/420
Likewise, for the 2nd fraction, since 84 × 5 = 420,
21/84 = 21 × 5/84 × 5 = 105/420
Add the two like fractions:
560/420 + 105/420 = 560 + 105/420 = 665/420
665/420 simplified gives 19/12
So, 40/30 + 21/84 = 19/12
In mixed form: 17/12

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad