Responsive percentages in a formula?

[Arashan]

Hello,

I am a bit of a novice, so will try to explain this the best I can. In cell A1 I have the number 100,000. Cell B1 has =SUM(0.8*A1) and Cell C1 has =SUM(0.2*A1). I want to have it so that if I change the number in A1 then the percentage value in B1 will change, but the value in C1 will remain the same.

So for example, if I change from 100,000 to 200,000 in A1, then the value in B1 would be 180,000, but it would remain 20,000 in C1 (since that is 20% of the original value in A1).

Is there a way to do this?

Thank you in advance.

 

[etaf]

you want to change from 80% to 90% of the value at 200,000,
what about 150,000, or any other value between 100,000 and 200,000