1. Adding integers

2. Today’s Objective
IWBAT add integers.

3. Example: -3, -2, -1, 0, 1, 2, 3 Definition
Integer – any positive or negative number, excluding fractions, decimals, or percents.
Example:
-3, -2, -1, 0, 1, 2, 3

4. But I don’t know how to add integers!!! I think that I am going to …
FREAK OUT!!!

5. No vorries children! Adding integers is not that different from adding whole numbers.

6. How do I Add Integers? There are 3 ways that I use to add integers:
1.) Number Line
2.) Counters
3.) Song

7. How do I Add Integers? The Number Line Method
To use the number line, follow these steps:
1.) Start at the point of the first number
2.) Then do one of two things:
a) If the second number is positive, go to the right the number of spaces
b) If the second number is negative, go to the left the number of spaces

8. How do I Add Integers? The Number Line Method
Simplify:
Move the point 7 spaces to the RIGHT 4 -3 -5 -4 -3 -2 -1 1 2 3 4 5 6 7 8 9

9. How do I Add Integers? The Number Line Method
Simplify: 4 + (-5)
Move the point 5 spaces to the LEFT 4 -1 -5 -4 -3 -2 -1 1 2 3 4 5 6 7 8 9

10. How do I Add Integers? The Number Line Method
Simplify:
Move the point 2 spaces to the RIGHT -5 -3 -5 -4 -3 -2 -1 1 2 3 4 5 6 7 8 9

11. How do I Add Integers? The Counters Method
To use the counters method, follow these steps:
1.) Make a T-Chart
2.) Use “+” signs to represent the positive number and “-” to represent the negative number
3.) Cross out every “+” that you have a “-” for
4.) Count what you have left. That is your answer. If you have more “+” left, your answer is positive; if you have more “-” left, your answer is negative.

12. How do I Add Integers? The Counters Method
Simplify 9 + (-5) 9 -5 - - + + + + - - + + - + + +

13. How do I Add Integers? The Counters Method
Simplify -8 3 + + - - - - + - - - -

14. How do I Add Integers? The Counters Method
Simplify -3 7 + + - - - + + + + +

15. The number line and counters methods only work with small numbers!!
So if you have bigger numbers (which you will), you need to use the next method:
The Song
A word of warning!!!!
The number line and counters methods only work with small numbers!!

16. How do I Add Integers? The Song Method
To add integers, simply sing this song to the tune of Row, Row, Row, Your Boat:
Same signs add and keep
Different signs subtract
Take the sign of the higher #
Then you’ll be exact!!

17. How do I Add Integers? The Song Method
Simplify
same or different
add or subtract
positive or negative

18. How do I Add Integers? The Song Method
Simplify
same or different
add or subtract
positive or negative

19. How do I Add Integers? The Song Method
Simplify (-20)
same or different
add or subtract
positive or negative

20. EXIT TICKET
1. (–2) + (–9) + 18
2. (–25) –11
–3 + –8