1. Objective: Students will add integers using models and rules (11-3).

2. Vocabulary  Zero pair – the result of pairing one positive counter with one negative counter.

3. Steps  “Place” all positive counters on the paper.  “Place” all negative counters on the paper.  Pair up all positive and negative counters.  Remove as many zero pairs as possible.  Remember zero pairs do not change the value of the problem.

4. Examples Use counters to find -4 + 3.

5. Examples Use counters to find -4 + 3. - - - - Place 4 negative counters on the mat to represent -4

6. Examples Use counters to find -4 + 3. - - - - + + + Place 4 negative counters on the mat to represent -4. Then place 3 positive Counters on the mat to represent 3.

7. Examples Use counters to find -4 + 3. - - - - + + + -+ + + - - - Place 4 negative counters on the mat to represent -4. Then place 3 positive counters on the mat to represent 3. Pair the negative and positive counters. Remove as many as possible.

8. Examples Use counters to find -4 + 3. - - - - + + + -+ + + - - - - Place 4 negative counters on the mat to represent -4. Then place 3 positive counters on the mat to represent 3. Pair the negative and positive counters. Remove as many as possible. Count the counters left on the mat. So, -4 + 3 = -1.

9. Examples Use counters to find -2 + (-2).

10. Examples Use counters to find -2 + (-2). - - Place 2 negative counters on the mat to represent -2.

11. Examples Use counters to find -2 + (-2). - - Place 2 negative counters on the mat to represent -2. Then place 2 more negative counters on the mat to represent the other -2. - -

12. Examples Use counters to find -2 + (-2). - - - -- - Place 2 negative counters on the mat to represent -2. Then place 2 more negative counters on the mat to represent the other -2. Since there are no positive counters you can not remove any zero pairs. So, -2 + (-2) = -4. - -

13. Rules for adding integers:  Read directions/copy problem.  If you have like signs (+,+ or -,-), you are to add and keep the same sign.  If you have unlike signs(+,- or -,+), you are to subtract and take the sign of the largest #.

14. Examples On a popular TV game show, a contestant has 200 points and then loses 500 points. What is the contestant’s score?

15. Examples On a popular TV game show, a contestant has 200 points and then loses 500 points. What is the contestant’s score? You need to find the sum of 200 + (-500). (Consider a number line.)

16. Examples On a popular TV game show, a contestant has 200 points and then loses 500 points. What is the contestant’s score? You need to find the sum of 200 + (-500). (Consider a number line.) -300 -200 -100 0 100 200 300

17. Examples On a popular TV game show, a contestant has 200 points and then loses 500 points. What is the contestant’s score? You need to find the sum of 200 + (-500). (Consider a number line.) -300 -200 -100 0 100 200 300 Start at 0 and go to 200 in the positive direction (right).

18. Examples On a popular TV game show, a contestant has 200 points and then loses 500 points. What is the contestant’s score? You need to find the sum of 200 + (-500). (Consider a number line.) -300 -200 -100 0 100 200 300 Start at 0 and go to 200 in the positive direction (right). From that point, go 500 in the negative direction (left).

19. Examples On a popular TV game show, a contestant has 200 points and then loses 500 points. What is the contestant’s score? You need to find the sum of 200 + (-500). (Consider a number line.) -300 -200 -100 0 100 200 300 Start at 0 and go to 200 in the positive direction (right). From that point, go 500 in the negative direction (left). You end at -300. So, 200 + (-500) = -300

20. Guided Practice State whether each sum is positive, negative, or zero. -5 + 3 -3 + 7

21. Guided Practice State whether each sum is positive, negative, or zero. -5 + 3 negative -3 + 7 positive

22. Find each sum. Use counters or a number line if necessary. 3 + (-1) 0 + (-2) -4 + (-8) 4 + (-6)

23. Find each sum. Use counters or a number line if necessary. 3 + (-1) 0 + (-2) 2 -2 -4 + (-8) 4 + (-6) -12 -2

24.  Find the sum of -4, 8, and -12.

25. -4 + 8 + (-12) 4 + (-12) -8