Finding the closest number in a random set

Question

Say I got a set of 10 random numbers between 0 and 100.

An operator gives me also a random number between 0 and 100. Then I got to find the number in the set that is

Answer 1

Someone tagged this question Mathematica, so here's a Mathematica answer:

set = {1,10,34,39,69,89,94,96,98,100};

opno = 45;

set[[Flatten[
  Position[set - opno, i_ /; Abs[i] == Min[Abs[set - opno]]]]]]

It works when there are multiple elements of set equally distant from the operator number.