Lattice Multiplication

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Lattice Multiplication

• By Mrs. Heter

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Upon completion of this exercise, you will
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Upon completion of this exercise, you will
Discover the history of lattice multiplication
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Upon completion of this exercise, you will
Discover the history of lattice multiplication
Identify the four step process for completing a 2
by 1 lattice
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Upon completion of this exercise, you will
Discover the history of lattice multiplication
Identify the four step process for completing a 2
by 1 lattice
Construct your own 2 by 1 lattice grid
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Upon completion of this exercise, you will
Discover the history of lattice multiplication
Identify the four step process for completing a 2
by 1 lattice
Construct your own 2 by 1 lattice grid
Apply the Lattice Method to multiplication
problems
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So, what is Lattice Multiplication, anyway?
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So, what is Lattice Multiplication, anyway?

• Lattice multiplication is a method of
  multiplication that will work for all multi-digit
  multiplication problems! Lattice keeps your
  numbers organized and provides a systematic way
  to solve multiplication problems.

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Is Lattice Multiplication New?
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Is Lattice Multiplication New?

• NO! In fact, the Lattice method of
  multiplication appears in the first printed
  arithmetic book. Printed in Treviso, Italy in
  1478 this book shows this exact method as well as
  some variations of the long multiplication
  algorithm commonly taught today.

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COOL!
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4 Simple Steps to Lattice Multiplication

• 1. Make the grid/ lattice
• 2. Write the factors outside the grid
• 3. Multiply
• 4. Add to get your answer

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(No Transcript)
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Step One Make the Lattice Grid

• First draw a box and divide it into 2 equal
  sections.

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Step One Make the Lattice Grid

• Next, divide those boxes diagonally from the top
  right to the bottom left corner.

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Step Two Write the factors on the grid

• Now what? Simple, ask someone to give you a
  multi-digit multiplication problem to solve! Now
  add these numbers to the grid.

43 x 5 ?
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Fill in the Lattice

• Fill in the numbers like this

4 3
5
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Step Three Multiply

• Now multiply!

43 x 5 ?
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Then Multiply the Outside!

• First multiply 5x3 and write your answer in the
  lattice as shown.
  

4
3
5
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Then Multiply the Outside!

• Next, multiply 5x4. Write your answer in the top
  left box of your lattice grid.
  

4
3
5
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Wait! Youre Not Finished Yet!
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Step Four Add the Inside

• Finally, add the numbers in the diagonals to get
  the solution.
  
• 5 is all by itself so simply bring
• that number down.

4
3
5
5
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Step Four Add the Inside

• Finally, add the numbers in the diagonals to get
  the solution.
  
• Next, add 1 0, and write the
• sum under the lattice.

4
3
5
5
1
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Step Four Add the Inside

• Finally, add the numbers in the diagonals to get
  the solution.
  
• Finally, bring down the 2.

4
3
5
5
1
2
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Now youve got your answer!
43 x 5 215
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Now You Try It.

• Using the graph paper in front of you, draw a
  square around any two of the blocks on your paper.

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Now You Try It.

• Next, divide those boxes diagonally from the top
  right to the bottom left corner.

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Fill in the Lattice

• Fill in the numbers like this

3 9
6
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Then Multiply the Outside!

• First multiply 6x9 and write your answer in the
  lattice as shown.
  

3
9
6
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Then Multiply the Outside!

• Next, multiply 6x3. Write your answer in the top
  left box of your lattice grid.
  

3
9
6
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Add the Inside

• Finally, add the numbers in the diagonals to get
  the solution.
  
• 4 is all by itself so simply bring
• that number down.

3
9
6
4
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Add the Inside

• Finally, add the numbers in the diagonals to get
  the solution.
  
• Next, add 5 8, and write the
• sum under the lattice.

3
9
1
6
4
3
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Step Three Add the Inside

• Finally, add the
• numbers in the
• diagonals to get
• the solution.
• Finally, add the 1 1
• And write the sum below
• the lattice.

3
9
1
6
4
3
2
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Now youve got your answer!
39 x 6 234
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Lets Practice Together!
Practice is FUN!
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Try 71 x 3
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Are you ready for more?????
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Ready, Set, Lets Solve Lattice Multiplication
Problems!

• Please open your math journal to page 231

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Try 8 x 45
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Try 5 x 23
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Try 6 x 431
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Hmmm, what will we need to do differently to
multiply a THREE digit number?
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Try 6 x 431
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Lets Take a Quick Lattice Multiplication Quiz to
see how much you remember!
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Yes or No?
CLAP your hands ONE TIME for YES.
STOMP your feet ONE TIME for NO.
Lattice multiplication is a NEW method of
multiplying numbers?
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No!
Lattice multiplication has been in use since the
late 1400s!
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Yes or No?
CLAP your hands ONE TIME for YES.
STOMP your feet ONE TIME for NO.
The process for solving Lattice Multiplication
involves 4 steps.
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4 Simple Steps to Lattice Multiplication

• 1. Make the grid/ lattice

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4 Simple Steps to Lattice Multiplication

• 1. Make the grid/ lattice
• Write the factors on the
• outside of the grid

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4 Simple Steps to Lattice Multiplication

• 1. Make the grid/ lattice
• 2. Write the factors on the
• outside of the grid
• 3. Multiply

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4 Simple Steps to Lattice Multiplication

• 1. Make the grid/ lattice
• 2. Write the factors on the
• outside of the grid
• 3. Multiply
• 4. Add to get your answer

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Congratulations!
Youve just learned how to solve multi-digit
multiplication problems using the Lattice
Multiplication Algorithm!
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Congratulations!
Now, finish the problems on the right column of
page 231. Ask your seat mate or raise your hand
if you need assistance.