Question 1123779
recall:


first you have the empty set: {}


So the empty set really has {{{0}}} elements, and it has just {{{1}}} subset (which is itself, the empty set).

It is like asking "There is nothing available, so what do you choose?" Answer "{{{nothing}}}"



then we have a set with one element: {apple} 

How many subsets does the set {apple} have?: the whole set ({apple}) and the empty set ( {} )

So any set with one element will have {{{2 }}}subsets.


you have a set with one element: {12} 

one element will have {{{2 }}}subsets, and they are: { } and {12}