How to register a function with changes in cells in Google sheets?

Question

Google Sheets

There is a table with conditions:
A1= "Starting price"
A2="Final price"
A3="% discount on the final price"
A4="discount in dollars"
A5="Dollar exchange rate"
A6="Discount in rubles"
A7="Difference between A1 and A2" taking into account the discount
The task is as follows:
If in A3 I indicate the discount in%, then the conversion is in rubles, the percentage of the discount in money is displayed in cells A4 and A6, and in cell A7 the difference is displayed taking into account the discount. BUT if we enter data in cell A4, then in cell A3 and A6 it is recalculated taking into account the entered data, as well as if, when making changes to cell A6, the values ​​of cells A3 and A4 are also recalculated.
In other words, how to realize the possibility of making discounts in various ways in%, in dollars, in rubles, and so that when changes are made, the recalculation is automatic.
Is this even possible in Google Docs?

Answer 1

1) It is not clear why this is necessary, because dollars are linearly dependent on rubles, which means that a 10% discount in rubles is the same discount in dollars.
2) It is better to attach a table, this will speed up the answer
3) Make both options and switch between them, for example, with a checkmark. There is a checkmark - 1st option, no checkmark - 2nd option.