Answers

Add 18/80 and 21/84

18/80 + 21/84 is 19/40.

Steps for adding fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 80 and 84 is 1680
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1680
2. For the 1st fraction, since 80 × 21 = 1680,
   18/80 = 18 × 21/80 × 21 = 378/1680
3. Likewise, for the 2nd fraction, since 84 × 20 = 1680,
   21/84 = 21 × 20/84 × 20 = 420/1680
4. Add the two like fractions:
   378/1680 + 420/1680 = 378 + 420/1680 = 798/1680
5. 798/1680 simplified gives 19/40
6. So, 18/80 + 21/84 = 19/40

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