1. Long Division: Using the Standard Algorithm

2. Warm Up
LESSON OBJECTIVE: SWBAT identify the parts of division problems in various forms, and explain and apply multi-digit division using the standard division algorithm
LANGUAGE OBJECTIVE: SWBAT discuss long division algorithm using correct vocabulary
On a school field trip, your class followed a treasure map and found a buried treasure! Imagine that your class has 25 students total, and that there were 1000 gold coins in the treasure chest.
How many coins does each
student get? Express your
answer in three different ways.
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In-Class Notes
Teacher should instruct students to use the warm up activity as they typically do in their classroom (ie, in notebook, independently or with their partners). Prompt students that they have 5 minutes to consider the warm-up and to find solutions/talk about their ideas.
Preparation Notes
Agenda

3. Warm Up
We found 1000 gold
coins, and need to divide them equally between the 25 students in our class.
Express the problem in three ways.
_____
25) 1000
1000 = 25
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In-Class Notes
Answers provided upon animation.
Preparation Notes
1000 ÷ 25 =
Agenda

4. We’ll check back on this problem in a little while!
Warm Up
So how many
coins does each student get?
_____
25) 1000
1000 = 25
1000 ÷ 25 =
We’ll check back on this problem in a little while!
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In-Class Notes
Answers provided upon animation.
Preparation Notes
Agenda

5. Remember: Launch Long division algorithm!
An algorithm is a formula or a set of steps for solving a problem.
Some strategies aren’t efficient when solving a division problem. SO… let’s take a look at the steps to solving the
Long division algorithm!
Be ready to share the four steps with your partner!
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In-Class Notes
Preparation Notes
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6. Launch http://www.youtube.com/watch?v=0uZiqk_ZdcA Agenda
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In-Class Notes
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7. Launch
With your partner, list the three ways to express the clam’s division problem.
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In-Class Notes
Students should be prepared to share their answers. HINT for students: The clam has one of the ways to express the problem!
Three ways to express the clam’s problem are as a fraction (64/2), number sentence/using division sign (64 ÷2) and with long division algorithm or the “tent” (as the clam has it written!).
Preparation Notes
Agenda

8. LONG DIVISION ALGORITHM
Launch
With your partner, list the three ways to express the clam’s division problem:
FRACTION
NUMBER SENTENCE
LONG DIVISION ALGORITHM
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In-Class Notes
Students should be prepared to share their answers. HINT for students: The clam has one of the ways to express the problem!
Have students go to board to show how each method of expression is written down. If students struggle with remembering ‘long division algorithm,’ remind them of the lesson objective and the fishy video.
Preparation Notes
Agenda

9. How many steps are there in the
Launch
How many steps are there in the
long division algorithm?
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In-Class Notes
Students should be prepared to share their answers. HINT for students: The clam has one of the ways to express the problem!
Three ways to express the clam’s problem are as a fraction (64/2), number sentence/using division sign (64 ÷2) and with long division algorithm or the “tent” (as the clam has it written!).
Preparation Notes
Agenda

10. How many steps are there?
Launch
How many steps are there?
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In-Class Notes
There are 4 steps. What are they? Divide, Multiply, Subtract, Bring Down.
How can we remember the steps? Daddy, Mommy, Sister, Brother
Preparation Notes
Agenda

11. DIVIDE MULTIPLY SUBTRACT BRING DOWN Explore Agenda
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In-Class Notes
Teacher should prompt students - what is the next picture going to be? What is the next step?
Preparation Notes
BRING DOWN
Agenda

12. Let’s apply the steps to long division to a new problem:
Explore
Let’s apply the steps to long division to a new problem:
84 ÷ 6 = ?
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In-Class Notes
Here students divide a 2 digit dividend by a 1 digit divisor.
Ask students what they think would be more efficient – equal grouping or the algorithm? Why?
Invite equal grouping proponents to the board to show how they would solve the problem.
Preparation Notes
Agenda

13. ✗ ✗ Explore Set up the problem: 84 ÷ 6 = ?
in the long division algorithm looks like which of the options below?
CHOICE A CHOICE B CHOICE C ?
6) 84
84 = ? 6 84
6 ) ?
6 = ? 84
? ) 6
84 = ? 6 ✗ ✗
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In-Class Notes
Why would you eliminate Choice A? Why would you eliminate Choice B? How do you know where to place the numbers in the algorithm? (ie, ID vocab words dividend, divisor, quotient from number sentence and plug in to algorithm).
If students aren’t grasping concept readily, review example from diamond robbery in Lesson One.
Preparation Notes
Agenda

14. 1 1 Explore STEP ONE: DIVIDE 8 ÷ 6 =
Follow along with the Guided Practice Worksheet!
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In-Class Notes
Students will follow prompts on Guided Practice Worksheet and work through the following slides together with teacher. At each step, see who did the same actions as modeled in the powerpoint (ie, stand up if you had the same answer), or ask students to predict next step.
Preparation Notes
Hand out worksheet named Guided Practice. Students should be ready to follow along and predict answers.
We divide the dividend by the divisor.
Agenda

15. 6 6 Explore STEP TWO: MULTIPLY 6 x 1 = We multiply Agenda
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In-Class Notes
Students follow along with guided practice worksheet. .
Preparation Notes
We multiply
Agenda

16. 2 2 Explore STEP THREE: SUBTRACT 8 – 6 = We subtract Agenda
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In-Class Notes
Students follow along with guided practice worksheet.
Preparation Notes
We subtract
Agenda

17. 4 Explore STEP FOUR: BRING DOWN We bring the 4 down Agenda
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In-Class Notes
Students follow along with guided practice worksheet. Note that “What number do we bring down” is one of the questions on the worksheet. We have now finished the first round of the 4 steps. Does anyone know what we should do next?
Preparation Notes
We bring the 4 down
Agenda

18. NOW WHAT??? Explore Agenda (Time on this slide - min) Time passed
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Preparation Notes
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19. 4 4 Explore STEP ONE: DIVIDE 24 ÷ 6 = We divide Agenda
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In-Class Notes
Students follow along with guided practice worksheet
Preparation Notes
We divide
Agenda

20. 2 4 24 Explore STEP TWO: MULTIPLY 6 X 4 = We multiply Agenda
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In-Class Notes
Students continue to predict/copy steps onto worksheet.
Preparation Notes
We multiply
Agenda

21. Explore STEP THREE: SUBTRACT 24 – 24 = We subtract Agenda
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In-Class Notes
Students continue to predict/copy steps onto worksheet.
Preparation Notes
We subtract
Agenda

22. There is no number to bring down – we’re almost DONE!
Explore
STEP FOUR: BRING DOWN
There is no number to bring down – we’re almost DONE!
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In-Class Notes
Students continue to predict/copy steps onto worksheet.
Preparation Notes
Agenda

23. Don’t forget to check your answer! 6 X 14 = Explore The opposite of
84 ÷ 6 = 14 is
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In-Class Notes
Teacher reinforces inverse relationship of multiplication and division (ie, addition is the opposite of subtraction just like _____ is the opposite of division (multiplication)).
Preparation Notes
6 X 14 =
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24. Checking your answer 84 14 x 6 Explore Agenda
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In-Class Notes
THIS IS AN ALGORITHM. An algorithm is a formula or set of steps for solving a problem. Can anyone remember the steps of the algorithm for long division?
Preparation Notes
Agenda

25. Practice 1
Let’s try one more problem – try it alone and we’ll review it together!
144 12
= ?
144 ÷ 12 = ?
What do these number sentences look like in the long division algorithm? ?
12) 144
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In-Class Notes
Students will flip over their worksheet and work through problem without the guidance of the modeled format. Allow students to work through problem on their own if they’d like (and we’ll all follow along together after)
Preparation Notes
Agenda

26. 1 1 Practice 1 STEP ONE: DIVIDE 14 ÷ 12 = What are we dividing?
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In-Class Notes
Students follow along/check their work. Note that the numbers we are working with are in pink.
Preparation Notes
What are we dividing?
We are dividing the dividend by the divisor.
Agenda

27. 12 12 Practice 1 STEP TWO: MULTIPLY 12 X 1 = We multiply Agenda
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In-Class Notes
Students follow along/check their work.
Preparation Notes
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28. 2 2 Practice 1 STEP THREE: SUBTRACT 14 – 12 = We subtract Agenda
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In-Class Notes
Students follow along/check their work.
Preparation Notes
Agenda

29. 4 Practice 1 STEP FOUR: BRING DOWN We bring down Agenda
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In-Class Notes
Students follow along/check their work.
Preparation Notes
Agenda

30. NOW WHAT??? Practice 1 Agenda (Time on this slide - min) Time passed
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Preparation Notes
NOW WHAT???
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31. 2 2 Practice 1 STEP ONE: DIVIDE 24 ÷ 12 =
We divide the dividend by the divisor.
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In-Class Notes
Students follow along/check their work.
Preparation Notes
Agenda

32. 24 24 Practice 1 STEP TWO: MULTIPLY 12 x 2 = We multiply Agenda
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In-Class Notes
Students follow along/check their work.
Preparation Notes
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33. Practice 1 STEP THREE: SUBTRACT 24 - 24 = We subtract Agenda
We subtract
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In-Class Notes
Students follow along/check their work.
Preparation Notes
Agenda

34. There is no number to bring down – we’re almost done!
Practice 1
STEP FOUR: BRING DOWN
There is no number to bring down – we’re almost done!
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In-Class Notes
Students follow along/check their work.
Preparation Notes
Agenda

35. Don’t forget to check your answer! 12 X 12 = Practice 1
The opposite of
144 ÷ 12 = 12 is
12 X 12 =
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In-Class Notes
Students follow along/check their work.
Preparation Notes
Agenda

36. Checking your answer 144 12 x 12 Practice 1 Agenda
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In-Class Notes
Students follow along/check their work.
Preparation Notes
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37. Summary How many steps are there to the long
division algorithm? What are they?
2. What is the trick the video taught us to
remember the steps?
3. Is there anything confusing about using
the long division algorithm?
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In-Class Notes
Answers:
1. Students may answer that there are 4 steps (divide, multiply, subtract, bring down), or 5 if they count checking their steps.
2. The trick is to use the family Daddy (divide), Mommy (multiply), Sister (subtract) and Brother (bring down).
3. Students provide answers.
Preparation Notes
Agenda

38. Practice 2 Agenda (Time on this slide - min) Time passed
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39. 1000 = So how many coins does each student get?
Exit Ticket
So how many
coins does each student get?
_____
25) 1000
1000 = 25
1000 ÷ 25 =
Show your work using the
long division algorithm.
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In-Class Notes
Answers provided upon animation.
Preparation Notes
Agenda

40. Each student gets gold coins!
Exit Ticket
So how many
coins does each student get?
Each student gets gold coins!
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In-Class Notes
Answers provided upon animation.
Preparation Notes 40
Agenda

41. Assessment Agenda (Time on this slide - min) Time passed
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