This is Not the right place to ask these questions, use Code Project.
But since I'm here.
If you are talking about 200 - 100 = 100 then
1 Dim Num1 as Integer = 200
2 Dim Num2 as Integer = 100
3
4 Dim Result as Integer
5
6 Result = Num1 - Num2
7
8 ' output result to where ever you want.
9 'Such as
10
11 TextBox1.Text = Result