Inform your students how different tasks in the class have different weights. For example, a teacher may state that homework counts for 10 percent of a grade, weekly quizzes count for a total of 50 percent and the midterm and final may count of 20 percent each, totaling 100 percent.
Outline that each component must be multiplied by the percentage it is responsible for in the overall grade. Using the percentages from Step 1, the equation is as follows:
(Total Homework Completed / Total Homework Assigned) x .10 = Homework Score
(Weekly Quiz Score Total / Weekly Quiz Score Potential Total) x .50 = Quiz Score
Midterm x .20 = Midterm score
Final x .20 = Final Score
Note that because there is more than one homework assignment and weekly quiz, those values must be divided first before they are multiplied. The decimal represents the percentage each component carries in the overall equation. Point out that the decimals must equal "1" when added together.
Plug in the values. Using the example in Step 2, assign values to what the student might have done over the course of the class. For example, say he completed 16 of 20 homework assignments, scored a total of 850 out of a possible 1,000 points on quizzes and received a 91 on the midterm and an 84 on the final. The math is as follows:
(16/20) x .10 = 8
(850/1000) x .50 = 42.50
91 x .20 = 18.2
84 x .20 = 16.8
Add the values of each together in order to get the weighted grade. In the example, the student's total is as follows:
8 + 42.50 + 18.20 + 16.8 = 85.5 or 86 when rounded-up. This student receives a B in the class.
Write a problem on the board using new scores and instruct your class to compute the answer on their own. Between your demonstration and the students completing the math problem, they will see how it is calculated. Instruct them to show their work in case they make a mistake so you can help them find it.
Inform your students that when calculating unweighted grades each component has an equal weight. For example, a teacher might count completed homework as 20 percent and four separate tests as 20 percent each. Therefore each component is equal.
Outline an equation to solve as an example. Because each value is equal in the example in Step 1, they are all multiplied by the same percentage. Remember the total value of the decimals must equal "1."
(Completed Homework / Total Homework Assignments) x .20 = Homework Score
Test 1 x .20 = Test 1 Score
Test 2 x .20 = Test 2 Score
Test 3 x .20 = Test 3 Score
Test 4 x .20 = Test 4 Score
Note, as in Section 1, the division of the homework assignments must occur before the number is multiplied. This is because there is more than one homework assignment.
Assign values to the equation. For example, say the student completed 15 of 20 of her homework assignments and scored a 93, 88, 75 and 96 on the four tests, respectively. The equation is as follows:
(15/20) x .20 = 15
93 x .20 = 18.6
88 x .20 = 17.6
75 x .20 = 15
96 x .20 = 19.2
Add the values together in order to get a final grade. Using the example, the equation is:
15 + 18.6 + 17.6 + 15 + 19.2 = 85.4 or 85 when rounded down. She receives a B for her work in the class.
Write another problem on the board using equal values and instruct the students to solve the equation on their own. Also, instruct them to show their work so it can be fixed if incorrect.