This might be simple, but I am approaching two months of writing spreadsheets and my head is failing

If Column A has a value of 9.1234, I want to round this, which I can do by various methods to the nearest whole number of 9. However, if I want to use the value in column A, I want to use the rounded version of 9 to complete further calculations, and not 9.1234.

Any ideas?

Many thanks, your help has been invaluable