1. Objective: Students will subtract integers using rules (11-4).

2. Steps Place all the counters the table for the 1 st number of the problem. Place all the counters the table for the 1 st number of the problem. Since subtraction is the opposite of addition, remove the number of counters of the 2 nd number to equal the number being subtracted. Since subtraction is the opposite of addition, remove the number of counters of the 2 nd number to equal the number being subtracted. Count the counters still on the table. Count the counters still on the table.

3. Rules for subtracting integers: Read directions/copy problem. Read directions/copy problem. First # always stays the same. First # always stays the same. Subtraction goes to addition. Subtraction goes to addition. Change the sign of the 2nd # only. This should be the opposite. Change the sign of the 2nd # only. This should be the opposite. Follow your rules for addition. Follow your rules for addition.

4. Examples Use counters to find -5 – (-2). Use counters to find -5 – (-2).

5. Examples - -- -- Place 5 negative counters in the box.

6. Examples Use counters to find -5 – (-2). Use counters to find -5 – (-2). - -- -- - - - - - Place 5 negative counters in the box. Circle the 2 counters to represent sub- tracting -2.

7. Examples Use counters to find -5 – (-2). Use counters to find -5 – (-2). - -- -- - - - - - - -- Place 5 negative counters in the box. Circle the 2 counters to represent subtracting -2. Remove the circled set and count the remaining ones. So, -5 – (-2) = -3.

8. Examples Use counters to find -5 – 4. Use counters to find -5 – 4.

9. Examples - -- -- Place 5 negative counters in the square.

10. Examples Use counters to find -5 – 4. Use counters to find -5 – 4. - -- -- Place 5 negative counters in the square. To subtract 4 you must remove 4 positive counters. But you can’t remove 4 positive counters because there are none. You must add 4 zero pairs. Then you can remove 4 positive counters. - - - - - - - - - + + + +

11. Examples Use counters to find -5 – 4. Use counters to find -5 – 4. - -- -- Place 5 negative counters in the square. To subtract 4 you must remove 4 positive counters. But you can’t remove 4 positive counters because there are none. You must add 4 zero pairs. Then you can remove 4 positive counters. Count the remaining counters. - 5 – 4 = - 9 - - - - - - - - - + + + + ---- ---- -

12. Rules for subtracting integers:

13. Guided Practice Find each difference. Use counters or a number line if necessary. 3 – (-1) 3 – (-1) - 4 – (-4) - 4 – (-4) 6 - 8 6 - 8

14. Guided Practice Find each difference. Use counters or a number line if necessary. 3 – (-1) 4 3 – (-1) 4 - 4 – (-4) 0 - 4 – (-4) 0 6 – 8 -2 6 – 8 -2