1. Adding & Subtracting Integers!

2. Let’s have some fun and sing! (to the tune of Row, Row, Row Your Boat)
Same signs add and keep
Different signs subtract

3. Keep the sign of the higher number
Then you’ll be exact

4. Different signs subtract Keep the sign of the higher number
Let’s try that again!
Same signs add and keep
Different signs subtract
Keep the sign of the higher number
Then you’ll be exact

5. Now, let’s add a second verse for subtracting integers!
Change the minus to a plus
Change the sign of next
Then all you do is add them up
As if they were a plus

6. Put it all together! Same signs add and keep Different signs subtract
Keep the sign of the higher number
Then you’ll be exact
Change the minus to a plus
Change the sign of the next
Then all you do is add them up
As if they were a plus

7. Are you ready?? What You Will Learn
California State Standard
5NS2.1 Add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results.
Some definitions related to integers.
Rules for adding and subtracting integers.
Different methods that will work for you.
Are you ready??

8. Definition
Positive number – a number greater than zero. 1 2 3 4 5 6

9. Definition
Negative number – a number less than zero. -6 -5 -4 -3 -2 -1 1 2 3 4 5 6

10. Definition
Opposite Numbers – numbers that are the same distance from zero in the opposite direction -6 -5 -4 -3 -2 -1 1 2 3 4 5 6

11. Definition
Integers – Integers are all the positive whole numbers and all of their opposites, including zero. 7
opposite -7

12. The absolute value of +9 or of –9 is 9. Definition
Absolute Value – It is the distance a number is from zero on the number line.
The absolute value of
+9 or of –9 is 9.

13. Negative Numbers Are Used to Measure Temperature

14. Negative Numbers Are Used to Measure Below Sea Level30 20 10
-10
-20
-30
-40
-50

15. Hint
If you don’t see a negative or positive sign in front of a number it is positive. 9 +

16. Integer Addition Rules
Rule #1 – If the signs are the same, pretend the signs aren’t there. Add the numbers and then put the sign of the addends in front of your answer.
9 + 5 = 14
= -14

17. Integer Addition Rules
Rule #2 – If the signs are different pretend the signs aren’t there. Subtract the smaller from the larger one and put the sign of the one with the larger absolute value in front of your answer. =
Larger abs. value
Answer = - 4
9 - 5 = 4

18. Integer Subtraction Rule
Subtracting a negative number is the same as adding a positive. Change the signs and add.
2 – (-7)
is the same as
2 + (+7)
2 + 7 = 9

19. Let’s try another
-2 – (+7)
is the same as
-2 + (-7)
= -9

20. One more…
2 – (+7)
is the same as
2 + (-7)
= -5

21. One Way to Add and Subtract Integers Is With a Number Line
I like to call this,
“Stand – Turn – Walk”
Or STW - + 1 2 3 4 5 6 -1 -2 -3 -4 -5 -6

22. Stand at the first integer.
Let’s give it a try!
Stand at the first integer.
If the problem is -
-2 + (3)
Stand at -2 - + 1 2 3 4 5 6 -1 -2 -3 -4 -5 -6

23. Turn toward the function sign -2 + (3) You are standing in front of -2 Now turn toward the positive integers on the number line.

24. Walk forward or backward according to the sign of the second integer
Since the (3) is positive, you will walk forward from the -2 three spaces. The number you stop on is your answer. The answer is positive 1.
-2 + (3) = 1

25. You have learned lots of things
About adding and subtracting
Integers. Let’s review!

26. Integer Addition Rules
Rule #1 – If the signs are the same, pretend the signs aren’t there. Add the numbers and then put the sign of the addends in front of your answer.
9 + 5 = 14
= -14

27. Integer Addition Rules
Rule #2 – If the signs are different pretend the signs aren’t there. Subtract the smaller from the larger one and put the sign of the one with the larger absolute value in front of your answer. =
Larger abs. value
Answer = - 4
9 - 5 = 4

28. Integer Subtraction Rule
Subtracting a negative number is the same as adding a positive. Change the signs and add.
2 – (-7)
is the same as
2 + (+7)
2 + 7 = 9!

29. Let’s try some problems using Stand, Turn, Walk
-6 + (3)
= -3
2 + (-4)
= -2

30. Another?
4 – (-2)
= +6
-4 – (-2)
= -2

31. Aren’t integers
interesting?