MULTIPLICATION EQUATIONS - BALANCE SHEET
Many of the equations can be solved mentally, therefore emphasize that the lesson will focus on a process for solving equations. Explain that understanding this process for solving equations will help them solve more difficult equations that cannot be worked mentally.
Divide the class into groups, provide each group with approximately 30 two color chips. Provide each group with a sheet of unlined 8 x 11 paper and have them draw a line dividing the paper in half, creating their balance sheets. Write the equation 3m = 12 on the overhead below the balance sheet and show its model. Place three yellow chips on the left side of the line and 12 red chips on the right side of the line.
Tell the students to think of the two sides of the line as the two sides of a balance scale. Explain that it is very important to keep both sides of the balance sheet or scale balanced. Emphasize that as long as the same work is performed on both sides of the line a balance is maintained.
Show the students how rearranging the chips helps to illustrate the value of each yellow chip. Dividing both sides by 3 leaves 1 yellow chip on the left balanced with 4 red chips on the right.
Stress the importance of showing each step. Explain that the yellow chip is the variable m or unknown number. Work the problem on the overhead showing each step by modeling it with chips.3m = 12 (Write the equation.) 3m/3 = 12/3 (Write and model the need to divide both sides by 3.) m = 4 (Write the new equation.)
Have the students model several other simple multiplication equations using chips. Ask the students to record their steps for each equation as they model it with chips.
SOLVING DIVISION EQUATIONS
Remind the students that they can use inverse operations to solve equations. Demonstrate how to solve the equation c/4 = 20 using the inverse operations.
c/4 = 20 (Write the equation.) c/4 (4) = 20 (4) (Show the need to multiply both sides by four.) c = 20 (Write the new equation)
Provide students with several division equations to solve independently.
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These pages were developed through GirlTECH, a teacher training sponsored by the Center for Research on Parallel Computation (CRPC), a National Science Foundation Science and Technology Center.