mathematical operations on text boxes

[vb_student]

Hello
I have got the following code

 CableLos = CableLoss.Text + OTSR_splitterLoss.Text

i stick the value 3 in cableloss.text
and 3 in OTSR_splitterloss.text

and i get the value 33 !!

can you guys tell me how to do a sum on these two text boxes.