Enter a number into a cell that does a sum in background and returns the value

Dear All

I have been searching the web to help me with my latest excel issue, and I think it comes back to having to use VBA to solve it. It is a basic cash checker worksheet that i need to work out cash values.

I want to enter a value into B2 (for example 3) that will return the answer of B2*B3 (3*£50) and put it in cell B2. (£150) I hope i have been clear enough to make sense.

I have uploaded the worksheet becuase i have no clue about VBA's, how to work them out or even where to put them, I was hoping someone has the knowledge to help me?


Thanks for helping
Gary