1. Modeling one-step addition/subtraction equations
Today’s Lesson:
What:
Modeling one-step addition/subtraction equations
Why:
. . . so I can explore the meaning of an equation through an equation modeling lab.
How:
. . . by engaging in the lab, correctly answering 3 out of 4 questions on the exit ticket, and completing my homework!

2. How is the Inverse Property of Addition used when solving an equation?

3. In your own words, describe the Golden Rule of Algebra.

4. Brainstorm . . .
What is an equation ??

5. YES! Both sides equal 8 so they are balanced!
Is this a true equation?
3 + 5 = 4 + 4
3 + 5
4 + 4 8 8
YES! Both sides equal 8 so they are balanced!

6. 3 + 2 1 + 3 5 4 3 + 2 = 1 + 3 Is this a true equation?
NO! 5 is “heavier” than 4!

7. What does “x” have to equal in order for the scale to stay balanced?
5 + 5 10 10
x = 2
because = 10!

8. Modeling Equations Lab
In this lab, we will use algebra tiles in order to model the
process of solving equations!
Here are the tile pieces we will use . . .

9. Example: x + (-2) = 3
To solve the above equation, we will isolate “x”. To do this, we need to get rid of the 2 negative tiles that are with “x”. How can we get rid of the 2 negatives?
What is the additive inverse (opposite) of -2?
So, we will add two positives to BOTH sides of the equation because it needs to STAY BALANCED!! Watch . . .
Once the zero pairs are removed, the tiles left are the answer . . .
By making zero pairs! +2
x = 5

10. Let’s do #1 together . . . 2 2 + 3 = 5 Add 3 neg. to both sides.
Left: and Right: 3 2
2 + 3 = 5

11. #2 is subtraction . . . KCC! x = 7 7 - 2 = 5 Add 2 pos. to both sides.
Left: and Right: 0
x = 7
7 - 2 = 5

12. Your Turn . . .
You will have approximately 20 minutes to finish lab on your own. Ask questions if you have them!
We will go over discussion questions together (but answer them on your own first).
Last, you will take an Exit Ticket, so try your best!!
Tip: Use KCC for ALL subtraction equations in the lab!
Good Luck! Get to work! 

13. Let’s discuss (after most have finished) . . .
Discussion Questions:
What is the main goal when solving an equation?
Why did we use a picture of a balance in our model?
What is the “Golden Rule of Algebra.”
When making “zero pairs,” what property are we applying?
5. Why is the Inverse Property (zero pairs) a necessary step in the process?
Finding out what x is by isolating it.
Because both sides of equation must be equal or balanced.
What we do to one side of the equation, we must do to the other!
Inverse Property of Addition (zero pairs)
Zero pairs are necessary in order to isolate the variable.

14. Homework/ practice Due by next class!
IXL: 7th Grade, S.3

15. END OF LESSON