Perhaps you don't need calculus, trigonometry and geometry, specifically, but you sure do need to know the rules of ordering, and of basic math and algebra!!!!
While we all rely on our computers to do most of our calculations, we have to know enough to recognize when there is an error in our spreadsheet formulas. Just think of how often we look at a number on a tax return, recognize from our base of tax knowledge that this number is wrong, go back and check and find that we did not check a box that should have been checked, or we had checked one that should not have been checked or left out some critical info? Those who use Turbo Tax and screw up are a perfect example of the truth that no tax program [and no spreadsheet] can give you the right result if the person using it does not have a good understanding of the rules that govern the forms.
We all tend to rely on our tools to "do it for us", but unless you have the knowledge to recognize an error, based on your knowledge of the subject behind the form, you are not a professional. Sorry if that sounds harsh, but while I think it is highly appropriate to let advanced students use calculators, for example they should not be allowed until after the student has a solid grounding in mathematics. Just as before you touch a tax program, you should study tax law, or else you do not even understand some of the questions you must answer on that tax program.