I am trying to creat a 3 column petty cash table so that no matter if you fill in one column the other two will update automatically.

so my columns are as follows

A= amount (excluding tax)

B = Tax

C = Total including tax

Example

if tax was set to 10%

and I entered in A: amount of $100

then B: Tax would be $10 (A* tax) &

then C: Total would be $110 (A+B)

Alternatively if I enter in the C: total amount of $200

Then A: Amount would be $181.82 calculated on

=(C/((Tax*100)+100))*100

(tax is a percetnage)

then B: would be $18.18 (C-A)

**My question is how do I phrase each of the statements so that is does not create a circular reference?**

I have been trying IF statements but with no luck as yet.

Can you do IF statements that are only calculated, if a user enters a value? (as a possible solution)

can anyone help

thanks johnny