Add 42/84 and 30/40
42/84 + 30/40 is 5/4.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 84 × 10 = 840,
42/84 = 42 × 10/84 × 10 = 420/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
30/40 = 30 × 21/40 × 21 = 630/840 - Add the two like fractions:
420/840 + 630/840 = 420 + 630/840 = 1050/840 - 1050/840 simplified gives 5/4
- So, 42/84 + 30/40 = 5/4
In mixed form: 11/4
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/84+60/40 42/84+30/80 42/84+90/40