# Lesson: Equations: Division using Variables

Tara Smith E.l. Haynes Pcs Washington, DC
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### Lesson Objective

SWBAT solve division equations with variables

### Lesson Plan

Materials Needed: DN Worksheet, white board, dry erase markers, IND Practice worksheet
Vocabulary: multiplication, operations, equations, variables, signal words, division

……….

Do Now (3 -5 min): Each student is given a DN worksheet and asked to complete it independently.

Opening (2 -3 min): Teacher says, “Yesterday, we learned about using variables in multiplication word problems. Today we are going to work on setting up and solving division equations. Remember, we are still practicing identifying Signal Words that tell us it is a division problem as well as setting up the equation to solve. By the end of this lesson, you will all be able to set up and solve one-step division equations with variables. Are there any questions?”

Direct Instruction (10 – 12 min): Teacher then writes the following equation on the board x ÷ 7 = 8 and says,  “Remember, since X is the variable I will be using a * to mean multiplication during this lesson. Ok, watch as I solve this equation using the algebraic process. It will mirror the process for addition and subtraction problems, only I will have to rely on my multiplication and division fact knowledge.”

Step 1: Write out equation as is x  ÷ 7 = 8
Step 2: Get the variable by itself 56 = 8 * 7
Step 3: Solve for the variable x = 56
Step 4: Check variable answer 56 ÷ 7 = 8
8 = 8

Teacher then continues, “Alright, did everyone see how I did that? It is the same process we have be using for the last three days. However, who can tell me something I could have done if I didn’t know the answer to 8 * 7? [add 8 seven times, add 7 eight times, use a multiplication chart, etc.] Those are all great answers, and they show me that you all are understanding division and multiplication. Now, I have a surprise. In the DC-CAS, you will not be asked to solve word problems using division. Therefore, to practice solving equations with division, you will only have to determine the variable, set up the equation, and then solve. Watch as I do this one.”

The teacher writes the following problem on the board and then works through with these steps:

Example 1:                                                             x ÷ 5 = 9

Step 1: Write out equation x ÷ 5 = 9
Step 2: Get the variable by itself x = 5 * 9
Step 3: Solve for the variable x = 45
Step 4: Check variable answer x ÷ 5 = 9
45÷ 5 = 9

Teacher then continues, “Now, when you look at this problem, you will notice that when checking your answer, you simply put in all the numbers to see if the problem is true. What can you do if you do not know how to solve this problem? [You can make it a multiplication problem, you can draw a picture, you can use a division chart] OK, great, you all are ready to go over a couple more problems before doing some on your own!”

Guided Practice (8 -10 min): Teacher then completes Example 2 for guided practice. An additional problem can be added if students are having difficulty.

Example 2: x ÷ 13 = 5

Step 1: Write out equation x ÷ 13 = 5
Step 2: Get the variable by itself x = 5 * 13
Step 3: Solve for the variable x = 65
Step 4: Check variable answer 65 ÷ 13 = 5
5 = 5

Independent Practice (10 min): Teacher gives each student their own copy of the Independent Practice (IND) worksheet. Teacher reminds students to use all four steps to solve the problem. Teacher circulates the room to answer individual student’s questions.

Closing (2-3 min): Teacher calls the attention of the students back toward the front of the class to quickly review the answers to the Independent Practice worksheet/ ask what we learned about.

### Lesson Resources

 IND division single step algebra problems   Classwork 347 DN multiplication single step algebra problems   Starter / Do Now 273