Goals:

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• Goals
• Homework Issues
• Exploration 3.15
• Start 3.4
• Exploration 3.18

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Homework Issues
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• Youre getting great at the how. Lets start
  focusing on the why.
• Dont tell me the algorithm works because of
  place values. Most algorithms work because they
  take into account place. How is the particular
  algorithm unique?

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Contexts This was the first problem. Did people
look at the wrong figure?

• Repeated Addition
• A ball costs 3.How much does 2 balls cost?
• Certain Number of Measure Units Number Line.
• If Bob walks 3 mph for 2 hours, how far will he
  have walked?
• Area
• What is the area of a carpet this is 3ft by 2 ft?
• Combinations
• If I own 3 skirts and 2 shirts, how many
  combinations can I wear?

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• Be careful with story problems. You still had
  issues with the subtraction ones
• Comparison vs Missing Addend

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Exploration 3.15
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Exploration 3.15

• 1. Work alone to come up with a story problem.
• 2. Share your story with other group members.
• a. Sort your stories in to groups.
• b. Try to name these groups.
• c. Well discuss as a class
• 3. For homework Due Monday

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2c. Different Groups of Story Problems
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3.4
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1. Division Measurement Problems

• Just like in the other mathematics operations, we
  have different measurement issues
• If we have 15 ounces of orange juice and 3
  glasses, how much will go in each glass if we
  want everyone to receive the same amount of
  juice? (Continuous)
• If I have 15 toy trucks, and want to give the
  same number of toy trucks to 3 people, how many
  toy trucks does each person get? (Discrete)

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2. Models for Division

• Partitioning Model
• If I have 15 toy trucks, and want to give the
  same number of toy trucks to 3 people, how many
  toy trucks does each person get?

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• Repeated Subtraction.
• If I have 15 trucks, how many people can I give 3
  trucks to?

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• Some ways to help you realize what type of model
  you have
• Think about your units
• What would your diagram look like?
• How did we think about the above in teh previous
  examples?

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• Thinking in terms of parts and the whole
• Partitioning
• Repeated subtraction

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2. Terminology

• b na iff anb
• b is the dividend
• n is the divisor
• a is the quotient
• a and n are the factors of b and b is a multiple
  of a and n.

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3. The number line!

• We use the number line with multiplication when
  we thought about continuous models, or
  multiplication as repeated addition.
• We can use the number line here to show division
  as repeated subtraction.

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3. What Properties Hold for Division?
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4. Dividing by ZeroChuck Norris can divide by
zero

• Why cant we?

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5. Division with Remainder

• What does it mean to have a remainder
• in terms of a problem?
• in terms of algebra?

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Exploration 3.18
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• 1. Do by yourself, then discuss with your group.
• 2.
• a.

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• b.
• c.

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• d.