Adding Integers with and without Models

1. Adding Integers with and without Models September 20, 2012

2. Modeling Integer Addition with Counters + + • Modeling integer addition with counters: • represents a positive integer and represents a negative integer • Add the number of counters represented by each integer • When modeling integers a create a zero pair and cancel each other out • The remaining counters signify your answer

3. Modeling Integer Addition with a Number Line • Modeling integer addition with a number line • Moving right on the number line represents a positive integer and moving left on the number line represents a negative integer • Start at Zero and move the number and direction indicated by the first integer • From that number, move the number and direction indicated by the second integer • The number where you end is your answer

4. Model each problem using counters and a number line 1.

5. Model each problem using counters and a number line 2.

6. Model each problem using counters and a number line 3.

7. Model each problem using counters and a number line 4.

8. Adding Integers without Models • To add integers with the SAME SIGN: • Find the sum of their absolute values • Use the sign of the two integers • To add integers with DIFFERENT SIGNS: • Find the difference of their absolute values • Use the sign of the integer with the greatest absolute value

9. Answer each question without using models 5.

10. Answer each question without using models 6.

11. Answer each question without using models 7.

12. Answer each question without using models 8.

13. Additional Practice 9. The temperature outside at 8:00 a.m. was oF At 12:00 p.m. the temperature was oF. What was the change in temperature?

14. Additional Practice 10. On an underwater expedition, a diver started at a depth of 125 ft. If she dove 39 ft. further, what is her depth now?