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2-2 Adding Integers Pg. 82 Adding Integers 3 Ways!

Essential Question  How do you add positive and negative numbers?

4 3 Ways to ADD Integers  1. Integer Chips  2. Rule/Song  3. Number Line 4

Adding and Subtracting Integers Brain-Pop gintegers  Write down 2 facts from the clip…  1.  2.

6 Integer Chips  Each chip has a yellow side and a red side.  Yellow is POSITIVE  Red is NEGATIVE 6

7 Practice with Chips  Represent A. 4 B. -8 C. -3 D. 2 E. 0 7

8 In the Black or in the Red?  When business records were kept by hand, accountants used red ink for expenses and black ink for income. If your income was greater than your expenses, you were “in the black.” If your expenses were greater than your income you were “in the red.”  8

9 In the Black or in the Red?  Solve this problem:  Linda owes her sister $6 since she helped her babysit. She earns $4 delivering papers with her brother. Is Linda “in the red” or “in the black?” 9

10 Using Integer Chips  The first way to add integers is to use integer chips. 10

11 Opposites Cancel  When we first introduced INTEGERS we learned that every integer has an OPPOSITE.  When you combine OPPOSITES, they equal 0. They cancel. (Represent the following equations using integer chips.) A = 0 B = 0 11

12 Steps: - Use chips to represent the first number. - Use chips to represent the second number. Remember: Yellow-Positive & Red-Negative

13 MORE Steps:  Cancel out any zero- pairs.  Whats left? How many? What color? 13

Find each sum. Example 1 –4 + 8 The signs are different so were finding the difference. Think: 8 – 4 = 4. 4

= 13 The signs are the same so I put a negative in front. = -13 = 11 Examples 2&3

16  NOW : Gather 5 yellow chips and 9 red chips. Find the total value for each set of chips. Always use 5, -9 as your starting point.  a. original set of chips = ____ b. add 3 yellow chips = ____ c. remove 3 red chips = ____ d. remove 2 yellow chips = ______  e. add 2 red chips = ______ 16

17 TRY THESE:  A =  B =  C =  D. 3 + (-6) =  E = 17

18 Getting Harder...  7 + _____ = 1  ____ = -2  -3 + _____ = -6 18

19 Even harder...  What are two combinations of chips that would equal

20 What if I don’t have chips?  You can DRAW integer chips.  Example:

21 Integer Lab- Sums  Positive Plus Positive

22 Integer Lab- Sums  Negative Plus Negative

23 Integer Lab- Sums  + Plus -/- Plus

24 Integer Lab - Sums  1. The sum of two positive integers is ___________________ because _________________________ _________________________ ________. 24

25 Integer Lab - Sums  1. The sum of two positive integers is POSITIVE because both numbers are positive. 25

26 Integer Lab - Sums  2. The sum of two negative integers is ___________________ because__________________ _________________________ _______________. 26

27 Integer Lab - Sums  2. The sum of two negative integers is NEGATIVE because both numbers are negative. 27

28 Integer Lab - Sums  3. The sum of a positive number and a negative number _________________________ _________________________ _________________________ _________________________ _________________________ 28

29 Integer Lab - Sums  3. The sum of a positive number and a negative number varies. You will subtract the numbers and take the larger- looking number’s sign. 29

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 = = -14

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 = = 4 Larger Answer = - 4

32 Integer Addition Song  To the tune of Row-Row-Row-Your-Boat...  Same signs ADD and Keep!  Different signs SUBRTACT, take the sign of the higher number, then you’ll be exact. 32

33 3 Ways to ADD Integers  1. Integer Chips  2. Rule/Song  3. Number Line 33

Solving Using a Number Line 1. Start at zero 2. Move either left or right the number of spaces from zero 3. From where you landed move the number of spaces left or right that the second number indicates 4. Where you land is the answer to the equation

Example 4 Use a number line to find each sum. – –7 12 – = –12 –10 –8 –6 –4 –2 0

Use a number line to find each sum. Example 5 2 –14 –12 –10 –8 –6 –4 –2 0 –7 + (–4) –7 +(–4) –7 + (–4) = –11

–12 –10 –8 –6 –4 – –12 –10 –8 –6 –4 – Example 6 and 7

Practice  Page 84  (2-10) even

Work Session  Page 84  (14-28; 34-44)  GRADED

Homework  Workbook pg. 14  All problems