I can divide fractions, including mixed numbers, using the standard algorithm.

1

• I can divide fractions, including mixed numbers,
  using the standard algorithm.

I will be able to apply the algorithm to find 4
out of 5 quotients.
Warm Up Analyze this student's work. Find the
mistake and then redo it using the correct
algorithm. Student directions find the sum
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Algorithm to Divide Fractions

1. Rewrite the first fraction.
2. Change the division sign to multiplication.
3. Flip the second fraction upside down (the
   reciprocal).
4. Multiply
5. Simplify

? "Dividing fractions, as easy as pie, Flip the
second fraction, then multiply." ?
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But why?
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(No Transcript)
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Try It!How would you use 10 to prove
this idea?

• 10 divided by tells us to divide 10 by
• 5 then multiply by 2. Do this!

Reciprocal 10 times tells us to multiply
by 2 and divide by 5. Do this!
Did we get the same solution?
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Reciprocal

• When you flip the second fraction, you are
  writing that fractions reciprocal.

3
5
5
3
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Example 1
1
1
2
3
Rewrite
.
1
2
2

1
3
3
8
Example 2
4
4
5
9
Rewrite
1
4
9
9
4
1
.


4
1
5
5
5
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Dividing Mixed Fractions

1. Change mixed numbers into improper fractions.
2. Multiply by the reciprocal.
3. Reduce (simplest form, use common factors)

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Example 3
1
6
1
2

9
3
10
20

3
9
.
1
10
3
1
1

2
20
9
3
6
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Reflect and Assess
I can divide fractions, including mixed
fractions, using the standard algorithm.
I will be able to apply the algorithm to find 4
out of 5 quotients.
T-Q-R
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Classwork
4)
5)
Reflection What was one easy concept from this
lesson today and what is a concept you will still
need to work on? (ex. of concepts simplifying,
multiplying, converting)
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Classwork
4)
5)
Reflection What was one easy concept from this
lesson today and what is a concept you will still
need to work on? (ex. of concepts simplifying,
multiplying, converting)
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answers

• 56/55 1 55/56 2. 55/56
• 26/21 1 5/21 4. 35/43
• 5. 26/27