Answers

Add 18/84 and 21/40

18/84 + 21/40 is 207/280.

Steps for adding fractions

1. 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
2. For the 1st fraction, since 84 × 10 = 840,
   18/84 = 18 × 10/84 × 10 = 180/840
3. Likewise, for the 2nd fraction, since 40 × 21 = 840,
   21/40 = 21 × 21/40 × 21 = 441/840
4. Add the two like fractions:
   180/840 + 441/840 = 180 + 441/840 = 621/840
5. 621/840 simplified gives 207/280
6. So, 18/84 + 21/40 = 207/280

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