Add 42/21 and 20/40
1st number: 2 0/21, 2nd number: 20/40
42/21 + 20/40 is 5/2.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 21 × 40 = 840,
42/21 = 42 × 40/21 × 40 = 1680/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
20/40 = 20 × 21/40 × 21 = 420/840 - Add the two like fractions:
1680/840 + 420/840 = 1680 + 420/840 = 2100/840 - 2100/840 simplified gives 5/2
- So, 42/21 + 20/40 = 5/2
In mixed form: 21/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/21+20/40 42/21+20/80 42/21+60/40 42/63+20/40