VBA - Simple example for passing a variable between modules

After getting to know VBA quite well there is still one issue I am having, I can't seem to get my head around passing values between modules. I hope someone here might be able to aid me in a simple theoretical example that will help me and hopefully others.

Sub module1()

   Dim x As Integer

   'general code
   'general code
   'general code

   x = Sheet1.Range("A1").Value
   call module2

   'continue code

End Sub

Sub module2()

   Dim y As Integer

   y = x + 10

End Sub

All I am after is for someone to point me in the right direction on how to pass variable x to the second module, and then return y back to module1 and continue with the new calculated value.

Many thanks in advance!

Ryan.