Your spreadsheet layout seems very complex and cumbersome to me. I would
suggest doing a Google on spreadsheet layout etiquette as well. If a
problem is set out logically, the answer is usually much simpler. Now,
can you do the calculations without VBA code?

I would do it as follows: See below in your original message.

Now that we have done this in Excel, let's see how we can code it.

Your code will need to look something as follows:

Sub CalcAcrossManySheets()

Dim VAR01 as single (or long, however you need to define it)
Dim VAR02 as single
etc.

Worksheets("Sheet 1").Select
Range("A2").Value = VLOOKUP(Range("B2"),etc.

' For sheet  3 defining the formulas  will be similarly easy.

' Now select sheet 1 again as the active sheet, and transfer the
values across.

End

Personally, I would stick with the Excel formulas. But since you need
the practice, go for it. The advantage doing it with VBA code is that
the casual user will not be able to change the formulas in the
spreadsheet. Because there are no formulas. Only values. Lastly, you
will have to ensure that the user then has an easy way to activate this
piece of code, else they will type values all over the place, and will
never understand why nothing updates.