Are there 21 different positive whole numbers such that the sum of their reciprocals is 1?
I'm not sure about this question
Yes.
1/2+1/3 = 5/6
= 35/36
=
We can keep doing this forever so the sum of any even number of reciprocals of natural numbers can represent
Adding a last number of 1/6^n produces 1, so the sum of any odd number of reciprocals of 1atural numbers can be 1