Transcript Long Division Lesson Plan

Long Division: Using
Standard Algorithm
Adapted from 21st Century Lessons
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Objectives
• Students will be able to indentify the parts of
division problems in various forms.
• Students will be able to explain and apply
multi-digit division using standard algorithm.
• Students will be able to discuss long division using
correct vocabulary.
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Vocabulary
• Algorithm: A formula or set of steps for
solving a problem.
• Division: Splitting of large numbers into equal
groups of smaller numbers.
• Dividend: Number being divided.
• Divisor: Number you are dividing by.
• Quotient: Answer to a division problem.
Vocabulary Video
http://youtube.com/watch?v=0RCjWZe0qBQ
On a school field trip, your class
Warm Up
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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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.
_____
1000 =
1000 ÷ 25 = 25) 1000
25
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Warm Up
So how many
coins does each
student get?
1000 =
25
1000 ÷ 25 =
_____
25) 1000
We’ll check back on this problem in a
little while!
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With your partner,
list the three ways
to express the
clam’s division
problem.
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With your partner,
list the three ways to
express the clam’s
division problem:
FRACTION
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NUMBER
SENTENCE
LONG
DIVISION
ALGORITHM
The Steps to Long Division Video
http://www.youtube.com/watch?v=0uZiqk_ZdcA
How many
steps are
there in the
long division
algorithm?
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How many
steps are
there?
12
Let’s apply the steps to long division
to a new problem:
84 ÷ 6 = ?
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Explore
DIVIDE
MULTIPLY
SUBTRACT
BRING DOWN
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Set up the problem: 84 ÷ 6 = ?
in the long division algorithm looks like which of
the options below?
CHOICE A
CHOICE B
?
84
6)?
84
?)6
6) 84
6 =?
84
84 = ?
6
84 = ?
6
✗
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CHOICE C
✗
STEP ONE: DIVIDE
1
8÷6=
Follow along with the
Guided Practice
Worksheet!
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1
We divide the
dividend by the
divisor.
STEP TWO: MULTIPLY
6
6x1=
We multiply
17
6
STEP FOUR: BRING DOWN
4
We bring the 4 down
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STEP THREE: SUBTRACT
2
8–6=
We subtract
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2
NOW WHAT???
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STEP ONE: DIVIDE
4
24 ÷ 6 =
We divide
21
4
STEP TWO: MULTIPLY
24
6X4=
We multiply
22
24
STEP THREE: SUBTRACT
0
24 – 24 =
We subtract
23
0
STEP FOUR: BRING DOWN
There is no number
to bring down –
we’re almost
DONE!
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Don’t forget to
check your answer!
The opposite of
84 ÷ 6 = 14 is
6 X 14 =
25
Checking your answer
14
x6
84
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Practice 1
Let’s try one more problem – try it alone and
we’ll review it together!
144 ÷ 12 = ?
What do these number
sentences look like in the
long division algorithm?
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144
=?
12
?
12) 144
Practice 1
STEP ONE: DIVIDE
1
14 ÷ 12 = 1
What are we dividing?
We are dividing the dividend by the divisor.
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Practice 1
STEP TWO: MULTIPLY
12
12 X 1 =
We multiply
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12
Practice 1
STEP THREE: SUBTRACT
2
14 – 12 =
We subtract
30
2
Practice 1
STEP FOUR: BRING DOWN
4
We bring down
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Practice 1
NOW WHAT???
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Practice 1
STEP ONE: DIVIDE
2
24 ÷ 12 =
2
We divide the
dividend by the
divisor.
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Practice 1
STEP TWO: MULTIPLY
24
12 x 2 =
We multiply
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24
Practice 1
STEP THREE: SUBTRACT
24 - 24 =
0
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We subtract
0
Practice 1
STEP FOUR: BRING DOWN
There is no number
to bring down –
we’re almost done!
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Practice 1
Don’t forget to
check your answer!
The opposite of
144 ÷ 12 = 12 is
12 X 12 =
37
Practice 1
Checking your answer
12
x 12
144
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Exit Ticket
So how many
coins does each
student get?
1000 =
25
1000 ÷ 25 =
_____
25) 1000
Show your work using the
long division algorithm.
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Exit Ticket
So how many
coins does each
student get?
Each student gets
gold coins!
40
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Summary
1. 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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Credits
Original lesson designed by Catherine Murphy &
Sarah Kelly. 21st Century Lessons. Funded by the
American Federation of Teachers. Retrieved
from http://www.sharemylesson.com
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