Find the number of subsets? (There is no proper solution for the duplicate question, please provide proper proof ) The number of subsets {1,2,…,n} with odd cardinality is ?

(Is it asking about number of subsets, we have to take power set then?)
For $n&gt;0$ There are half subset containing an odd  and half containing an even number of elements

The set of subsets has $2^n$ elements so the number of subsets with odd cardinality

is half $2^n$ that is $2^{n-1}$

Hope this helps
For $n&gt;0$ There are half subset containing an odd  and half containing an even number of elements

The set of subsets has $2^n$ elements so the number of subsets with odd cardinality

is half $2^n$ that is $2^{n-1}$

Hope this helps