# Lesson: Equations: Set Up with Variable Review

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### Lesson Objective

SWBAT set up an equation with a variable from word problem

### Lesson Plan

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

……….

Do Now (3 -5 min): Each student is given a DN worksheet and asked to complete it independently. The worksheet reviews equations with addition, subtraction, multiplication, and division.

Opening (3 -5 min): Teacher quickly reviews answers to the Do Now and then says, “Yesterday, we reviewed inequalities using variables in addition, subtraction, multiplication, and division word problems and we worked on understanding the properties of inequalities. Today we are going to learn about equations with variables. By the end of this lesson, you will all be able to set up equations with variables based on the information given in a word problem. Are there any questions?”

Direct Instruction (10 – 12 min): Teacher then writes the following equation on the board x + 7 = 47 and asks “You all have seen problems like this so much! Now, we need to know how to set up a problem on your own by reading a word problem. Watch as I show you how to set up an equation with variables from a word problem.”

Teacher writes the following example on the board:
Example 1:  There are 22 students in a class. There are _____ students absent today. Write an equation that represents the number of students who are in class today.
Teacher asks, “We need to know what the equation should look like? Keep in mind that this word problem is not asking us to solve the equation; it is just asking us to set up an equation! On the DC-CAS, you will be given a set up multiple choice answers such as the following.” Teacher writes the following on the board

A. 22 +
B. 22 –
C. 22 ×
D. 22 ÷

Teacher then continues, “After reading the word problem carefully, does anyone want to guess what the correct answer is?” [B] Awesome, and how did you get that answer? [I knew it was subtraction, I did it in my head, etc.] OK, when you are looking at this problem, you must look at the words carefully and then look at your choices carefully. I would think through the problem and look at all of the choices. When you look at all the choices, you can see that subtraction is the only one that makes sense in this case, because the problem asks how many students were absent. The answer will be a smaller number than the original number, 22, so you should not use multiplication or addition. Division also doesn’t make sense because the problem doesn’t say anything about forming groups of anything.”

Guided Practice (8 -10 min): Teacher says, “Ok, you all did great, now I want to do one more together before I give you all the chance to prove that you can do it on your own!” Teacher then completes Example 2 for guided practice. An additional problem can be added if students are having difficulty.

A. b ÷ 5 = 40
B. 5 + b = 40
C. b – 5 = 40
D. 5 × b = 40

Example 2: Max earned 5 stickers for every book he read. He earned 40 stickers in all for reading books. Which number sentence could be used to find b, the number of books Max read?

Note: The correct answer is D. Teacher must explain that this problem is tricky because it first appears to be a division problem.

Independent Practice (10 min
): Teacher gives each student their own copy of the Independent Practice (IND) worksheet. 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 equations with variables   Classwork DN add sub div mul single step   Starter / Do Now