Transcript Real-World Problems: Two

Chapter 7, Lesson 3
Multiplying Ones, Tens, and
Hundreds with Regrouping
What types of problems have we
solved so far?
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9x8
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90 x 8
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80 x 9
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900 x 8
Strategies we have
worked on . . .
Making ten and
subtract a group
If I know 4’s I can
double to make 8’s
Multiplying by ten . . .
Multiplying by one
hundred . . .
What types of problems have we
solved so far?
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23 x 4
Distributive Property
 Compose and
decompose into
place values
 Partial Products –
begin in either ones
or greatest place
value on the left
 Use doubling and
halving
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1. Multiply Ones, Tens, and
Hundreds with Regrouping
What is regrouping? Can you
give me an example with
addition?
15 x 5
4 x 31
Compare to the book
Breaking or decomposing into place values
 Work with the place value – 3 x 30 is not
the same as 3 x 3. We call the 30 – 3 tens
or thirty.
 We can write the whole value of the
multiplication problem and then add up all
the products.
 Shortcut can be writing the digits in the right
place value showing the regrouping above
the place value.
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Grade 3
Chapter 9 – Lesson 1 – RealWorld Problems: Multiplication
Use bar models to solve one-step
multiplication word problems
Bar models
What are unit bars? What do they
represent?
 How many units are in this diagram?
 How many dots are there in each unit?
 How many dots are there in all?
 How did you figure that out?
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What do we do when we solve
word problems?
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Read the problem
What do I have to answer?
Re-read each sentence and draw the bar
models, label the units. Adjust the bars as
necessary. Place your question mark.
Check your diagram.
Write the equations to solve the problems,
solve the problem
Check your answer. (Plug value back into the
diagram. Check the arithmetic.)
There are 5 boxes of pencils.
Each box contains 12 pencils.
How many pencils are there in all?
Compare to our book
What do you see as the same?
 What do you see as different?
 What does “twice” mean? Can you tell
your partner a problem that uses the
word twice?
 Partners do you agree with how they
used the word twice.
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Zach has 342 stamps.
Ron has twice as many stamps as Zach.
How many stamps does Ron have?