Answer
The total number of proper subsets is $7$.
Work Step by Step
Represented with the roster method, the set looks like this:
$\{3, 4, 5\}$
A set of $n$ elements has $2^n$ subsets.
This set has 3 elements; therefore, it has $2^3=8$ subsets.
However, we are asked for distinct subsets, so we have to take 1 from the result, as one of the subsets is going to be the set itself.
The total number of proper subsets is $8-1=7$.
