Add 84/80 and 20/42
1st number: 1 4/80, 2nd number: 20/42
84/80 + 20/42 is 641/420.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 80 and 42 is 1680
Next, find the equivalent fraction of both fractional numbers with denominator 1680 - For the 1st fraction, since 80 × 21 = 1680,
84/80 = 84 × 21/80 × 21 = 1764/1680 - Likewise, for the 2nd fraction, since 42 × 40 = 1680,
20/42 = 20 × 40/42 × 40 = 800/1680 - Add the two like fractions:
1764/1680 + 800/1680 = 1764 + 800/1680 = 2564/1680 - 2564/1680 simplified gives 641/420
- So, 84/80 + 20/42 = 641/420
In mixed form: 1221/420
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/80+40/42 84/80+20/84 84/80+60/42