That doesn't make any sense at all. The Arduino is so good at maths it will overcome my programming inadequacy and do so itself?
There is no math involved in making a for loop start at 4 and count down to zero. Stop making the excuse that your poor math skills have any bearing on this situation.
Why would I ask for help if I didn't need it?
I can't see that it is all that difficult to figure out that counting 3, 2, 1, 0 requires that you start at 3 and stop when you get to 0. Can you explain to me why that IS difficult?