Create cell Address from calculated number

Hello, please help me create a cell address using calculated data.

A1="P3" A2="right(A1,1)" B3="25"
B5 = B(A2) --or-- B(right(A1,1))

I wish for B5 to show 25.

I cannot figure out how to add the row number to the column letter.

Thanks!

Thank you very much -- sometimes SIMPLE is difficult to find.