Hey, I'm kind of new kind of not to programing, I know basic syntax's and all that, but for some reason I can't get a simple addition function to work. I'm trying to make a very simple calculator for my first project. It irretates me so much that subtraction, multiplication, division all work but not addition. It does 1+1=11, 25+4=254, etc... Any help? Here's the code:

Private Sub Add_bttn_Click()
Numb_3 = Numb_1 + Numb_2
End Sub
Private Sub Div_Bttn_Click()
Numb_3 = Numb_1 / Numb_2
End Sub
Private Sub Mul_Bttn_Click()
Numb_3 = Numb_1 * Numb_2
End Sub
Private Sub Sub_Bttn_Click()
Numb_3 = Numb_1 - Numb_2
End Sub