Do Now Exercise Please evaluate these problems in your notebooks, showing all work.

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Do Now ExercisePlease evaluate these problems in
your notebooks, showing all work.

• Evaluate
• 5! ?
• 7! 6! ?
• 42! / (45-6)! ?
• 11! / 6(7!) ?

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Solutions to the Do Now Exercise.

• 5! ?
• 7! 6! ?
• 42! / (45-6)! ?
• 4. 11! / 6(7!) ?

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Math Class 2/26/04

• Aim How do we use factorials to help us find
  combinations?
• Standards 1a, 2a, 4a, 4e, 4j, 5d
• Homework Complete any previous homework (Math
  Battles, worksheets, etc.) and put it in your
  portfolio. Portfolios will be collected on
  Friday. Also, complete the homework section on
  the hand-out Mr. Keech gives you.

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Homework

• Are there any questions about the homework that
  is due today?
• Please silently place your homework on your desk.
  Mr. Keech will collect it.
• Remember to write down and complete tonights
  homework assignment! (Its on the white board by
  the door.)

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Vocabulary Review

• Factorial
• Permutation
• Combination
• Pascals Triangle

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Mini-Lesson

• Follow along with Mr. Keech as he demonstrates on
  the chalkboard how to find combinations using a
  formula. The formula is very similar to the
  formula used for finding permutations, so pay
  close attention so that you dont get mixed up.

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Independent Practice / Group Work

• Following all directions, read and complete the
  classwork section of the sheet that Mr. Keech
  gives you. You may work in groups, but your
  noise level must remain at a 2. If you have any
  questions, feel free to ask each other for help.
  Remember to use Mr. Keech as a resource only
  after the whole groups ideas have been
  considered.

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Solutions to Group Work

• Look on with Mr. Keech as he shows some answers
  from the classwork on the chart-paper easel.
• !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
• Factorial Factorial Factorial
• Portfolios will be collected tomorrow.

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Share Out

• Its so easy to follow formulas weve done it
  before with areas and volumes, now we can do it
  with combinations and permutations!
• Did we achieve our aim today?
• What do factorials have to do with finding
  permutations and combinations?

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Summary

• Finding combinations is easy using this formula
• n!

______ k(n k)!
nCk
n the total number of items in a set or sample
space. k the size of the combination that you
make.
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Weve recently learned two new formulas. Here
they are. Make sure you have these in your
notebooks.
PERMUTATIONS (Used when order matters) nPk
COMBINATIONS (Used when order of picking is of no
significance) nCk
--------------------
n!
________
n!
_________
(n-k)!
k(n-k)!
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Homework Reminder

• DO YOUR HOMEWORK!
• DO YOUR HOMEWORK!
• DO YOUR HOMEWORK!
• DO YOUR HOMEWORK!
• DO YOUR HOMEWORK!
• DO YOUR HOMEWORK!
• Homework is written on the white board by the
  door.