INTEGERS

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INTEGERS

• Integers are the whole numbers and their
  opposites.
• Whole numbers- 0, 1, 2, 3, 4, 5..
• Integers- -1, -2, -3, -4, -5, -6..

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Number line

• -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7
• Positive
  numbers
• Negative numbers

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To add integers

• FIRST you must look to see if the numbers are
  alike or different
• Alike-both negative or positive
• Different-one negative and one positive
• If they are alike, you add the numbers and keep
  their sign(,-).
• If they are different, you subtract the numbers
  and take the larger digits sign.

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Example

• -6 -2
• The 6 and 2 are both negative. Because they have
  alike signs, you add the numbers and take the
  negative sign.
• -6 -2 -8

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Example

• -7 5
• These numbers have different signs. When they
  have different signs you subtract the numbers and
  take the larger digits sign. In this problem,
  the seven is larger and it is negative so the
  answer will be negative.
• -7 5 -2

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Try Some
1.) 12 -3 2.) 5 -8 3.) 13 (-45)
4.) 15 27 5.) 123 (-45) 6.) 89
(-24)
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Check Your Answers
1.) 12 -3 -15 2.) 5 -8 -13 3.) 13
(-45) -32 4.) 15 27 12 5.) 123 (-45)
78 6.) 89 (-24) -113
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To subtract integers

• Before you can subtract integers you have to
  change the problem to addition.
• FIRST- copy the first number and its sign.
• SECOND- change the subtraction to addition.
• LAST- change the second number to its opposite.
  Ex. 4 to 4 or 8 to -8

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Let us look at one

• -8 (-7)
• First- copy the 8
• Second- change the subtraction to addition
• Last- change the 7 to a positive 7
• Your problem should look like this when it is
  rewritten -8 7
• Now you can solve the problem following the
  addition rules!!!

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Try changing these subtraction problems to
addition
1.) -19 5 2.) 24 (-23) 3.) 81 123
4.) -34 (-14)
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Check your problems
1.) -19 -5 2.) 24 23 3.) 81 -123
4.) -34 14 Now try to solve the problems
using the rules for addition!
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Check your work
1.) 19 5 -19 -5 -24 2.) 24
(-23) 24 23 47 3.) 81 123
81 -123 -42 4.) 34 (-14) -34 14
-20
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Great!

• Now you are ready to lear to multiply and divide!