Add 42/12 and 42/40, Solve 3 6/12 + 1 2/40 as a fraction

Add 42/12 and 42/40

1^st number: 3 6/12, 2^nd number: 1 2/40

42/12 + 42/40 is 91/20.

Find the least common denominator or LCM of the two denominators:
LCM of 12 and 40 is 120

Next, find the equivalent fraction of both fractional numbers with denominator 120
For the 1st fraction, since 12 × 10 = 120,
42/12 = 42 × 10/12 × 10 = 420/120
Likewise, for the 2nd fraction, since 40 × 3 = 120,
42/40 = 42 × 3/40 × 3 = 126/120
Add the two like fractions:
420/120 + 126/120 = 420 + 126/120 = 546/120
546/120 simplified gives 91/20
So, 42/12 + 42/40 = 91/20
In mixed form: 411/20

MathStep (Works offline)

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