Add 70/21 and 90/6, Solve 3 7/21 + 15 0/6 as a fraction

Add 70/21 and 90/6

1^st number: 3 7/21, 2^nd number: 15 0/6

70/21 + 90/6 is 55/3.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 6 is 42

Next, find the equivalent fraction of both fractional numbers with denominator 42
For the 1st fraction, since 21 × 2 = 42,
70/21 = 70 × 2/21 × 2 = 140/42
Likewise, for the 2nd fraction, since 6 × 7 = 42,
90/6 = 90 × 7/6 × 7 = 630/42
Add the two like fractions:
140/42 + 630/42 = 140 + 630/42 = 770/42
770/42 simplified gives 55/3
So, 70/21 + 90/6 = 55/3
In mixed form: 181/3

MathStep (Works offline)

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