Cell drop down and If formulas

I have a spreadsheet with data and all of it organized in cell drop down menus, all the information is on the same sheet. My problem at the moment is that I need a cell drop down menu to show different options, depending on whats in another menu above it. I.E. (numbers themselves are just examples, not my real data) cell A1 has drop down options of 0, 10, 20, 30, etc. now if cell A1 shows 0, I need cell B1 to have a drop down option of 1 through 9, and if A1 shows 10, I need B1's drop down to then show 11 through 19.

I was planning to use an IF function for this, where if A1 equaled 0, B1 would show the drop down needed for it. However, B1 would change to whatever was in the drop down, but it wouldn't carry the drop down section with it. I'm having a difficult time with it and I can't find anything in a book or in the help function to help with a problem like this.
another attempt to explain what I am doing. I have drop down lists and if statements with them way down near the end of the sheet. I need them to come to an area near the top according to what a drop down list near the top says.
(so I need a drop down list to change the area below it to contain different drop down boxes and formulas)
Drop down in cell A1 can do numbers one through 10. when it says 1, there are drop down lists in cells A2 and A3, as well as if formulas next to them for calculations. when A1 changes to say two, there is a drop down list in A4 and the lists in A2 and A3 have changed, as well as the formulas next to them)