"Constant value button"

Hello! I'm trying to make a simple program using VB8. I'm trying to make a button which will multiple the input from a textbox, with the constant value of 1,8 (X*1,8). And then I'm trying to make the answer stay in the memory as It might has to be multiplied again. I'm totally lost and would really appriciate any kind of help.

f.ex. 1000*1,8=1800 -> 1800*1,8=3240

Thank you in advance,
Rawnney