Set a firm percentage mark for the child to attain on every test and assignment. This is similar to a pass/fail system. If he hits the mark, he can move on; if he doesn't hit the mark, he must repeat the material. This method is used in home education programs like K12. In these programs, students must attain an 80 percent in a unit, assessment or assignment to move on. This type of grading is ideal for children in elementary grades, because it produces less pressure than letter grades.
Give a letter grade from A to F for each assignment and for the overall score in a course. Parents of high school students may wish to use this type of grading, because it will be most recognizable by colleges. In this system, grades usually are figured like this: 90 to 100 percent is an A, 80 to 90 percent is a B, 70 to 80 percent is a C, 60 to 70 percent is a D and anything under 60 percent is an F.
Use the E-S-N-U system of grading. In this system, E stands for excellent, S for satisfactory, N for needs improvement and U for unsatisfactory. This system is good for younger students and for classes in which a grade is difficult to determine, such as physical education or art.
Avoid formal grading. With this system you simply encourage your child to learn instead of strive for a particular grade. The idea is that children can focus more on learning if they aren't concerned about what grade they will get. For example, a child can become unmotivated and even uninterested in a subject if he knows he is likely to get a low grade in the subject. A child who struggles with grades in math may decide that he "doesn't like math."