1. Adding and Subtracting Integers

2. Do Now
Write an expression and find the answer to this problem: Franklin the frog started at 6 on a number line. He then jumped back 8, forward 3, back 5, forward 11, and finally, back 1. Where did he end up? Show your work!

3. Do Now - Answer
Franklin the frog started at 6 on a number line. He then jumped back 8, forward 3, back 5, forward 11, and finally back 1. Where did he end up?

4. Objective
Today, I will add and subtract integers using three different methods.

5. Sign on a number Tells us the direction the number is moving
Positive (+) moves Right
Negative (-) moves Left

6. Sometimes it can be tricky!
What is the sign on the “8” in every problem below?
10 + 8
10 + (-8)
Vote only using your arms/ hands!
8 + (-10)

7. Now that we know the signs, time to check out 3 methods for adding and subtracting integers
1) Tile method
2) Forces method
3) Money Method

8. Tile Method This method relies on the use of zero pairs.
One positive and one negative make a zero pair because
Draw a + sign for positive
Draw a – sign for negative.

9. Tile Method – Example - 8 + 5 positive What’s left over? -3
negative
What’s left over? -3
(-3) + 6 – 1
What’s left over? 2

10. Forces Method
Imagine the numbers are trying to push an object in a certain direction
Positive forces go to the right.
Negative forces go to the left.
The number tells us how strong they are.
-11 12

11. Forces Method - Example
Are they working together or against each other?
If they are working together, add up their strengths
If they are working against each other, who wins and by how much? -5 -8
5 + 8 = 13
Negative direction
Answer: - 13 12
-10
Opposite!
Positive sign wins by 2!
Answer: +2

12. Money Method Imagine that the numbers are amounts of
money in a bank account.
means to spend, take out, or owe money.
means to deposit, put in, or earn money.

13. Example 350 – 425 (bank account) Answer: -$75
The first number tells how much you start with.
The sign and the next number tell what you do to that amount.
350 – 425 (bank account)
start with $350 in bank
friend buys you a ticket to the Warriors play-off game: owe $425
Answer: -$75
-130 – (credit card bill)
owe $130 on credit card bill
buy a burger and garlic fries at game - owe $14 more
Answer: - $144

14. Practice Time! Time to figure out which method works best for YOU!
With your partner complete parts 1, 2, 3, and 4.
You must get a star on each section to move on.
Once you have been starred, do number 5 (parts A through J – yes, that’s everything!)

15. Number 5 Answers:
A) 4 B) -14 C) -24 D) -61 E) -18 F) -185 G) -55 H) 23 I) -85 J) -11

16. Closure Review objective: Which method is the best? Why?
Today, I will add and subtract integers using three different methods.
Which method is the best?
Why?

17. Finding a difference! 48 -29 19 in. ? 29 48
What is the difference between 48 in. and 29 in.? 48
-29
19 in. ? 29 48

18. What about this difference?
A hiker climbed from -37 ft. to 214 ft. How far did she climb in total?
214
+37
251 ft.
+214
+37
-37
214

19. Practice!
In Utah, the high at noon would be 55˚ F then drop to 11 ˚ F by 9 pm. What is the difference in temperature?
Start: End: Difference: 44˚ F
After our first sushi roll, our bill was $14. After 13 rolls, our bill was $192. How much did the bill change by?
Start: End: 192 Difference: $178
3. When sick, Angela’s temperature was 101.8˚ F . The next day, her temperature was How much did her temperature drop?
Start: End: Difference: 2.2˚ F

20. More Practice
4. If you move a point on a number line from -9 to 10, how many units did you move it?
Start: End : 10 Difference: 19 u
5. Before school, the temperature was -4 ˚ F. After school, the temperature was 23 ˚ F. What is the difference?
Start: End : 23 Difference: 27 ˚F
Tony’s account was $303 before he went shopping. After, he saw that his account was
$ how much money did he spend?
Start: End : 303 Difference: $319