Add 6/4 and 90/21, Solve 1 2/4 + 4 6/21 as a fraction

Add 6/4 and 90/21

1^st number: 1 2/4, 2^nd number: 4 6/21

6/4 + 90/21 is 81/14.

Find the least common denominator or LCM of the two denominators:
LCM of 4 and 21 is 84

Next, find the equivalent fraction of both fractional numbers with denominator 84
For the 1st fraction, since 4 × 21 = 84,
6/4 = 6 × 21/4 × 21 = 126/84
Likewise, for the 2nd fraction, since 21 × 4 = 84,
90/21 = 90 × 4/21 × 4 = 360/84
Add the two like fractions:
126/84 + 360/84 = 126 + 360/84 = 486/84
486/84 simplified gives 81/14
So, 6/4 + 90/21 = 81/14
In mixed form: 511/14

MathStep (Works offline)

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