Adding Positive and Negative Numbers

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Adding Positive and Negative Numbers

• Or, why my brain hurts after
• math class

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• Basic Rules of Algebra
• Doing math operations with positive and negative
  numbers
• Addition Rule Of all the rules for positive and
  negative numbers, this one is the hardest to
  master. Try to remember that there are two ways
  of doing addition. One for numbers that have the
  same sign, and one for numbers having opposite
  signs.
• Rule 1. If the numbers have the same sign all
  you need to do is to add the numbers as you
  always have and use the sign of the numbers.

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Sample Problem 1

• Ex. - 23 5 ?
• Compare the two values and ask yourself what do
  you have more ofpostive?...negative?
• You have more negative, so your answer will be
  negative.
• Now ask youself How many more negatives do I
  have.
• The easy way to find this is to subtract small
  from big.
• 23 5 ?
• 18 ( Correct)
• Now place the negative sign in front of the
  answer.
• -18
• GOOD JOB!

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Sample Problem 2

• Ex. 235 -150 ?
• Compare the numbers.
• The sign will be ?
• Subtract the numbers
• 235 150 ?
• Your answer
• 85
• Excellent!

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• Spending Money

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In an Elevator
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On a Submarine
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How about a nice game?

• Time to play a game with the numbers.
• The positive numbers are the smilly faces.
• Make the negative numbers the hearts.

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6 (-10)
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Answer ?