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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.
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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.
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
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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.
Warm Up
Warm Up
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Express the problem in three ways.
We found 1000 gold coins, and need to divide them equally between the 25 students in our class.
_____ 25) 1000 1000 =
251000 ÷ 25 =
Warm Up
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So how many coins does each student get?
_____ 25) 1000 1000 =
251000 ÷ 25 =
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 LONG DIVISION ALGORITHM
NUMBER SENTENCE
The Steps to Long Division Video
http://www.youtube.com/watch?v=0uZiqk_ZdcA
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How many steps are there in the long division algorithm?
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How many steps are there?
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Let’s apply the steps to long division to a new problem:
84 ÷ 6 = ?
Explore
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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?
84 ? ) 6
84 = ? 6
84 6 ) ?
6 = ? 84
? 6) 84
84 = ? 6
CHOICE A CHOICE B CHOICE C
✗ ✗
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8 ÷ 6 =
STEP ONE: DIVIDE
We divide the dividend by the divisor.
1Follow along with the Guided Practice Worksheet!
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6 x 1 =
STEP TWO: MULTIPLY
We multiply
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6
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STEP FOUR: BRING DOWN
We bring the 4 down
4
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8 – 6 =
STEP THREE: SUBTRACT
We subtract
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NOW WHAT???
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24 ÷ 6 =
STEP ONE: DIVIDE
We divide
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4
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6 X 4 =
STEP TWO: MULTIPLY
We multiply
242 4
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24 – 24 =
STEP THREE: SUBTRACT
We subtract
00
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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 =
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Checking your answer
84
14x 6
Practice 1
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Let’s try one more problem – try it alone and we’ll review it together!
What do these number sentences look like in the long division algorithm?
? 12) 144
144 ÷ 12 = ? 14412 = ?
Practice 1
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14 ÷ 12 =
STEP ONE: DIVIDE
What are we dividing?
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We are dividing the dividend by the divisor.
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Practice 1
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12 X 1 =
STEP TWO: MULTIPLY
We multiply12
12
Practice 1
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14 – 12 =
STEP THREE: SUBTRACT
We subtract 22
Practice 1
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STEP FOUR: BRING DOWN
We bring down
4
Practice 1
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NOW WHAT???
Practice 1
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24 ÷ 12 =
STEP ONE: DIVIDE
We divide the dividend by the divisor.
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2
Practice 1
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12 x 2 =
STEP TWO: MULTIPLY
We multiply 2424
Practice 1
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24 - 24 =
STEP THREE: SUBTRACT
We subtract 0
0
Practice 1
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STEP FOUR: BRING DOWN
There is no number to bring down – we’re almost done!
Practice 1
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Don’t forget to check your answer!
The opposite of 144 ÷ 12 = 12 is
12 X 12 =
Practice 1
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Checking your answer
144
12x 12
Exit Ticket
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So how many coins does each student get?
_____ 25) 1000 1000 =
251000 ÷ 25 =
Show your work using the long division algorithm.
Exit Ticket
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So how many coins does each student get?
Each student gets gold
coins!40
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 usingthe 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
