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TRANSCRIPT
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Kindergarten
Operations & Algebraic Thinking: Part 2
www.njctl.org
2015-03-11
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Part 2 Unit Topics
· Exploring Subtraction· Word Problems· Modeling Subtraction
Click on the topic to go to that section
· Equal Sign· Connecting Cubes· Vertical Subtraction· Number Facts to 5· Addition & Subtraction Games· Addition & Subtraction Problem Solving
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Subtraction
Understand subtraction as taking apart and taking from.Provide children with opportunities to subtract items in their environment. Expose them to subtraction throughout the day by solving word problems that relate to life experiences. Decompose numbers less than 10 into pairs in more than one way. Fluently subtract within 5 by asking questions that foster sample subtraction (ex. There are 4 children at listening center. There are only 3 headphones. How many children should leave the center?)
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Subtraction Reading Books
Ten Little Mice by Joyce Dunbar. (Harcourt Brace & Co., 1990).
Elevator Magic by Stuart J. Murphy. (Harper Collins, 2000).
10, 9, 8, by Molly Bang. (Harper Collins, 2000).
Mmmm... Cookies! Simple Subtraction by Monica Weiss (Troll Associates,1992).
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Let's Explore Subtraction
Have the children act out the following problems.
1. There are three children playing with blocks. One moves to the drama center. How many are still playing with blocks?2. Four children are jumping. Two stop! How many are still jumping?3. There are five cookies on the plate. Tom and Sue each eat one. How many are left on the plate?4. Pass out 6 paper plates. Now take 2 away. How many plates are on the table now?5. Your teacher has 5 papers. There are 4 children at the table. She gives each child a paper. How many does she have left?
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Exploring Subtraction
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How many are left?
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Exploring Subtraction
How many are left?
Fish Bucket
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Pocket Subtraction
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Exploring Subtraction Pull down a number of space ships. Move some away to show the number taking off. Write how many are left.
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1 There are 4 birds on the line. If two fly away how many are left?
A 1
B 2
C 3
D 4
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2 There are 3 girls dancing. One has to go home. How many are left?
A 0
B 1
C 2
D 3
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3 There are 5 cars in the race . Two have to stop for gas. How many are still racing?
A 1
B 2
C 3
D 4
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4 There are 3 rocket ships . One blasts off. How many are still on the ground?
A 0
B 1
C 2
D 3
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Exploring Subtraction through Word Problems
· Have the children act out the stories.
· Tell and write the story. (Ex. There were 3 birds on the ground. One flew into a tree. How many are still on the ground?)
· Draw pictures to depict the number story. Then cross out the objects you take away.
· Write the number sentence to depict the story. 3-1=2
· Using counters and drawing pictures, the children can create their own stories on a white board or paper.
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Exploring SubtractionP
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Exploring Subtraction
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Exploring SubtractionP
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Exploring Subtraction
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Exploring Subtraction
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Exploring Subtraction
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5 There are five dolls at the store. The children buy three. How many are left at the store? Students should use counters.
A 5
B 4
C 3
D 2
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6 Mom put 4 apples in the basket. Three fell on the floor. How many are still in the basket? Students should use counters.
A 4
B 3
C 2
D 1
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7 The girl has 6 balloons. Two fly away. How many does she have now?
A 6
B 5
C 4
D 2
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8 There are 7 bunnies in the pen. Four are jumping out. How many will stay in the pen?
A 3
B 4
C 5
D 6
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Exploring Subtraction
Example there are four pebbles on the beach.The waves washes away two. How many are left?
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The teacher will make up a subtraction story and model on the board.
The children will then model teacher's actions using stick and counters at seats.
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Minus Symbol
Make up story to go with number of counters. Terminology- subtracting, minus, take away
Eventually write a corresponding number model (3-2).
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Minus Symbol
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Minus Symbol
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Our Subtraction Problems
Let's Subtract
minus symbol
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Our Subtraction Problems
Let's Subtract
minus symbol
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Our Subtraction Problems
Let's Subtract
minus symbol
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Concentration Problem (Next Page)
Discuss that the equation must match the picture problem.Have the students draw their own pictures the first time through to represent the equation. Students can use as a center activity.
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Concentration ProblemsMatch the problem to the equation
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Subtraction Shell Game
Player one. Player two.
-2
-10
-3-1 0 -2
-1
-30
-2-1
-3
-2
0-1-1The End
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Disappearing RabbitBe the first to move all bunnies from hat to fence.
PullPull
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Disappearing RabbitBe the first to move all bunnies from hat to fence.
PullPull
Students need dice with-1, -2 , 0, -1, -2 , -3
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9 Is this the subtraction symbol?
YesNo
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10 Which is the subtraction (minus) symbol?
A
B
C
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11 Do we take objects away when we subtract?
YesNo
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12 Which one shows minus 2?
A + 2
B = 2
C - 2
D 2
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Understanding SubtractionPull down dogs to represent first number.
Move some over to second number to show how many are leaving.Write how many are left.
4 1
4 2
5 4
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Understanding SubtractionWrite the numbers for problem.Pull down dogs to represent first
number. Move some over to second number to show how many are leaving. Write how many are left.
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Understanding SubtractionPull down counters for the first number.
How many are bouncing away? (second number).Write how many are left.
5 2
6 3
5 1
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Understanding SubtractionCreate your problem.
Pull down counters for the first number.How many are bouncing away? (second number).
Write how many are left.
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SubtractionEqual Symbol =
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SubtractionEqual Symbol =
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Equal Symbol =
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Equal Symbol =
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Have children work with you at their seats using any type of counters. Have them write problem on wipe board or paper.
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Equal Symbol =
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Connecting Cube ProblemsThe children work at seats while demonstration takes place on board. Write the problem and then use the cubes to figure out the answer.
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Connecting Cube ProblemsThe children work at seats while demonstration takes place on board. Write the problem and then use the cubes to figure out the answer.
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Connecting Cube ProblemsThe children work at seats while demonstration takes place on board. Write the problem and then use the cubes to figure out the answer.
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Subtracting Pattern
What is it?
10 - 1 = 9 - 1 = 8 - 1 = 7 - 1 = 6 - 1 = 5 - 1 = 4 - 1 = 3 - 1 = 2 - 1 = 1 - 1 =
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4 - 1 =
13 Solve this problem . Use your counters. 4-1 =
A 4
B 1
C 3
D 2
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6 - 4 =
14 Solve this subtraction problem. Use your counters. 6 - 4 =
A 4
B 3
C 2
D 1
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6 - 3 =
15 Is the answer to this problem 3?
YesNo
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3 - 3 =
16 Is the answer to this subtraction problem 1?
YesNo
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2 - 0 =
17 What is the answer to this problem? Use your counters. 2 - 0 =
A 2
B 4
C 0
D 1
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Subtracting Down
5 - 2 = 3 5-2 3
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4 - 3 = 1 4-3 1
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Subtracting DownMatch the problems.
6 - 3 = 3 2 - 1 = 1 5 - 5 = 0 4 - 3 = 1
5- 5 0
6-3 3
4-3 1
2-1 1
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Complete the Problems Subtracting Down
8-5
3-1
5-4
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Subtracting Down
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2 - 1 = 1 2-1 1
18 Are these the same problem?
YesNo
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4-3 =1
4-1 3
19 Do they represent the same problem?
YesNo
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3-2
20 Solve the problem. What is the answer?
A 2
B 1
C 3
D 0
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5-4
21 What is the answer to the problem?
A 4
B 3
C 2
D 1
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4-1
22 What is the answer to this problem?
A 0
B 1
C 2
D 3
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4-0
23 Is the answer to this problem 4?
YesNo
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Fluently Subtract The following pages provide fluency practice for subtraction within 5.
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3212
4123
Can You Subtract?
5-2
3-1
1-0
5-1
2-0
2-1
4-2
4-1
clickclick click click
clickclickclick
click
PullPull
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4
1
50
2
3
5-2
5-1
4-2
2-1
3-3
5-0
PullPull
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And the answer is?
Subtraction Facts
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4-0
24 Do not use counters. What is the answer?
A 1
B 2
C 3
D 4
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2-1
25 Do not use counters. What is the answer?
A 1
B 2
C 3
D 4
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4-1
26 Do not use counters. What is the answer?
A 1
B 2
C 3
D 4
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5-3
27 Do not use counters. What is the answer?
A 1
B 2
C 3
D 4
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3-1
28 Do not use counters. What is the answer?
A 1
B 2
C 3
D 4
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Addition/Subtraction Games
Demonstrate on the Interactive Whiteboard, then photocopy the game so the children can play at their tables with a partner. Besides the game board you will need dice marked with numbers and addition and subtraction symbols. This will reinforce the meaning of addition and subtraction symbols.
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Kangaroo Number Line
· Talk about the number line.· Discussion ... we can move forward (+)· We can move backward (-)· Eventually write equation to go with throw.· Need one die with +1, +2, +3, -1,-2, 0
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0 1 2 3 4 5 6 7 8 9 10
Kangaroo Number Line Subtraction/Addition
Roll dice and movethe kangaroo alongthe number line.Children can followalong with number linesand markers at seats.
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Plus or Minus Game(reinforce the meaning of the addition and subtraction symbols)
To Play:· You need two game boards.· Take turns rolling the cube.· + number (add that number of counters to your board)· - number (subtract that number from board *unless there are no counters on their board)· 0 means no move· Game ends when all squares are covered.· As the children get more proficient ... they can write a number sentence to record their moves.· You can set up at math center or use as whole group (pairing with partners at tables).· Game boards on next page.
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Player One Player Two
Plus or Minus Game
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Addition- Subtraction Activities· The following games can be set up as a math center or done as a whole group activity.· Demonstrate on the board first with student participation.· Then have students play with a partner using the game sheet at table.
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Addition/Subtraction Candy Game
Team A
Team B
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Addition/Subtraction Dinosaur Race Game
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Addition/Subtraction Bumble Bee Game
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Addition/Subtraction Fairy Tale Game
+
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porridge. Roll the dice and moveforward or backward dependingon the plus or minus sign.
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Addition & Subtraction Problem Solving
Click to Return to Table of Contents
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Problem Solving Addition or Subtraction
· Talk about the pictures and what is happening.· The children have to decide if this represents an addition or subtraction problem.· Are we adding objects or taking some away.· Do we use the + or - symbol?· Then choose the correct problem.
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Problem SolvingChoosing the Operation
5-2 3
5+2 7
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Problem SolvingChoosing the Operation
3-1 2
3+1 4
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Problem SolvingChoosing the Operation
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Create your own problem.Is this an addition or subtraction story?Do we use + or - symbol?
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Create your own problem.Is this an addition or subtraction story?Do we use + or - symbol?
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There are 5 apples.Joe eats 3.How many are left?
29 What problem matches the story?
A 5-3=2
B 5+3=2
C 5+3=8
D 5-3=1
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30 Bonnie finds 3 shells. Then she finds 2 more. How many does she have now? Do we add or subtract?
A +
B -
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31 Dom had 4 cars. He loses one. How many does he have now?
A +
B -
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Ryan finds 3 frogs.Ethan finds 3 frogs.How many frogs do they have altogether?
32 Which equation matches the story problem?
A 3+3=6
B 6-3=3
C 3+2=6
D 6-6=0
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Justin shoots 7 basketballs.3 go in the net.How many missed the net?
33 Find the equation that matches the story problem.
A 4+4=8
B 4+3=7
C 7-3=4
D 8-4=4
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Let's Get the Beat of Subtraction