If you're ever in a bind, you can use your calculator. Out of 22 problems if one problem is missed, then 21/22 questions are right. Take 21 divided by 22 and that's your percentage... But, I too, would be interested to know if there is some kind of EZ grader online version.

I've always just used my calculator - I don't even own a grade finder. I have a calculator at home and one at school, works perfectly.

Here's a general formula: To figure out the number of percentage points to deduct per question wrong, divide 1 by the number of questions. In this case, 1/22 gives .045454..., or 4.5454...%. Many teachers prefer exercises with 10, 20, or 25 possible points because it makes the math easier: with 10 points possible, each raw point is worth 10 percentage points; with 20, each raw point is worth 5; with 25, each raw point is worth 4 scaled points.