Add 21/14 and 21/18, Solve 1 7/14 + 1 3/18 as a fraction

Add 21/14 and 21/18

1^st number: 1 7/14, 2^nd number: 1 3/18

21/14 + 21/18 is 8/3.

Find the least common denominator or LCM of the two denominators:
LCM of 14 and 18 is 126

Next, find the equivalent fraction of both fractional numbers with denominator 126
For the 1st fraction, since 14 × 9 = 126,
21/14 = 21 × 9/14 × 9 = 189/126
Likewise, for the 2nd fraction, since 18 × 7 = 126,
21/18 = 21 × 7/18 × 7 = 147/126
Add the two like fractions:
189/126 + 147/126 = 189 + 147/126 = 336/126
336/126 simplified gives 8/3
So, 21/14 + 21/18 = 8/3
In mixed form: 22/3

MathStep (Works offline)

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