Some parents choose to grade simply by using a pass/fail system.
Some parents choose to award letter grades such as those awarded in a school system. Usually a letter grade is awarded on the following scale or something similar:
A 90 - 100
B 80 - 89
C 70 -79
D 60 - 69
F 59 or below |

How do you get these grades?
You can determine grades by effort, written seat work, tests, worksheets, projects, oral recitation, time spent, or any combination of these as you see fitting.
How do you find a letter/number grade average?
Simply divide the number of problems correct by the total number of problems. For example, if the page has 14 problems and your child got 12 correct, divide 12 by 14 to get .857 or 86%.
You would get a final grade using the same method. Simply add together all of your grades from tests, worksheets, and projects and divide by the total number possible. This will give you the final grade.
That's all there is to it! I hope this info helps!