Add 70/42 and 3/90, Solve 1 28/42 + 3/90 as a fraction

Add 70/42 and 3/90

1^st number: 1 28/42, 2^nd number: 3/90

70/42 + 3/90 is 17/10.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 90 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 42 × 15 = 630,
70/42 = 70 × 15/42 × 15 = 1050/630
Likewise, for the 2nd fraction, since 90 × 7 = 630,
3/90 = 3 × 7/90 × 7 = 21/630
Add the two like fractions:
1050/630 + 21/630 = 1050 + 21/630 = 1071/630
1071/630 simplified gives 17/10
So, 70/42 + 3/90 = 17/10
In mixed form: 17/10

MathStep (Works offline)

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