Slide 1 / 111 Slide / 111 Kindergarten Operations & Algebraic Thinking: Part 01-01 www.njctl.org Word Problems Modeling Subtraction Equal Sign Connecting Cubes Vertical Subtraction Number Facts to Slide / 111 Part Unit Topics Addition & Subtraction Games Click on the topic to go to that section Slide / 111 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 by asking questions that foster sample subtraction (ex. There are children at listening center. There are only headphones. How many children should leave the center?) Addition & Subtraction Problem Solving Slide / 111 Slide 6 / 111 Subtraction Reading Books Ten Little Mice by Joyce Dunbar. (Harcourt Brace & Co., 1990). Elevator Magic by Stuart J. Murphy. (Harper Collins, 000). 10, 9, 8, by Molly Bang. (Harper Collins, 000). Mmmm... Cookies! Simple Subtraction by Monica Weiss (Troll Associates,199). Click to Return to Table of Contents
Slide 7 / 111 Slide 8 / 111 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?. Four children are jumping. Two stop! How many are still jumping?. There are five cookies on the plate. Tom and Sue each eat one. How many are left on the plate?. Pass out 6 paper plates. Now take away. How many plates are on the table now?. Your teacher has papers. There are children at the table. She gives each child a paper. How many does she have left? How many are left? Slide 9 / 111 Slide 10 / 111 Pocket Subtraction Fish Bucket How many are left? Slide 11 / 111 Slide 1 / 111 1 There are birds on the line. If two fly away how many are left? down a number of space ships. Move some away to show the number taking off. Write how many are left. A 1 B C D
Slide 1 / 111 Slide 1 / 111 There are girls dancing. One has to go home. How many are left? There are cars in the race. Two have to stop for gas. How many are still racing? A 0 B 1 C D A 1 B C D Slide 1 / 111 Slide 16 / 111 There are rocket ships. One blasts off. How many are still on the ground? A 0 B 1 C D Word Problems Click to Return to Table of Contents Slide 17 / 111 Slide 18 / 111 through Word Problems Have the children act out the stories. Tell and write the story. (Ex. There were 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. = Using counters and drawing pictures, the children can create their own stories on a white board or paper.
Slide 19 / 111 Slide 0 / 111 Slide 1 / 111 Slide / 111 Slide / 111 Slide / 111 There are five dolls at the store. The children buy three. How many are left at the store? Students should use counters. A B C D
Slide / 111 Slide 6 / 111 6 Mom put apples in the basket. Three fell on the floor. How many are still in the basket? Students should use counters. 7 The girl has 6 balloons. Two fly away. How many does she have now? A B C D 1 A 6 B C D Slide 7 / 111 Slide 8 / 111 8 There are 7 bunnies in the pen. Four are jumping out. How many will stay in the pen? A B C D 6 Modeling Subtraction Click to Return to Table of Contents Slide 9 / 111 Slide 0 / 111 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. Minus Symbol Example there are four pebbles on the beach. The waves washes away two. How many are left? Make up story to go with number of counters. Terminology- subtracting, minus, take away Eventually write a corresponding number model ().
Slide 1 / 111 Slide / 111 Minus Symbol Minus Symbol Slide / 111 Slide / 111 Let's Subtract minus symbol Let's Subtract minus symbol Our Subtraction Problems Our Subtraction Problems Slide / 111 Slide 6 / 111 Let's Subtract minus symbol 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. Our Subtraction Problems
Slide 7 / 111 Slide 8 / 111 Subtraction Shell Game Concentration Problems Match the problem to the equation Player one. Player two. 0 0 - Disappearing Rabbit Be the first to move all bunnies from hat to fence. 0 - Disappearing Rabbit Be the first to move all bunnies from hat to fence. Slide 1 / 111 Yes No 0 Slide 0 / 111 Students need dice with,, 0,,, - 9 Is this the subtraction symbol? The End Slide 9 / 111 - Slide / 111 10 Which is the subtraction (minus) symbol? A B C
Slide / 111 11 Do we take objects away when we subtract? Yes No 1 Which one shows minus? A + B = C - D Slide / 111 Slide / 111 Understanding Subtraction down dogs to represent first number. Move some over to second number to show how many are leaving. Write how many are left. 1 Slide 6 / 111 Understanding Subtraction Write the numbers for problem. down dogs to represent first number. Move some over to second number to show how many are leaving. Write how many are left. Slide 7 / 111 Understanding Subtraction down counters for the first number. How many are bouncing away? (second number). Write how many are left. Slide 8 / 111 Understanding Subtraction Create your problem. down counters for the first number. How many are bouncing away? (second number). Write how many are left. 6 1
Slide 9 / 111 Slide 0 / 111 Subtraction Equal Symbol = Equal Sign Click to Return to Table of Contents Slide 1 / 111 Subtraction Equal Symbol = Slide / 111 Equal Symbol = Slide / 111 Equal Symbol = Slide / 111 Equal Symbol = m
Slide / 111 Slide 6 / 111 Connecting Cube Problems The children work at seats while demonstration takes place on board. Write the problem and then use the cubes to figure out the answer. Connecting Cubes Click to Return to Table of Contents Slide 7 / 111 Connecting Cube Problems The children work at seats while demonstration takes place on board. Write the problem and then use the cubes to figure out the answer. Slide 8 / 111 Connecting Cube Problems The children work at seats while demonstration takes place on board. Write the problem and then use the cubes to figure out the answer. Slide 9 / 111 Subtracting Pattern What is it? Slide 60 / 111 1 Solve this problem. Use your counters. = 10-1 = 9-1 = 8-1 = 7-1 = 6-1 = - 1 = - 1 = - 1 = - 1 = 1-1 = A B 1 C D - 1 =
Slide 61 / 111 Slide 6 / 111 1 Solve this subtraction problem. Use your counters. 6 - = 1 Is the answer to this problem? A B C 6 - = Yes No 6 - = D 1 Slide 6 / 111 Slide 6 / 111 16 Is the answer to this subtraction problem 1? Yes No - = 17 What is the answer to this problem? Use your counters. - 0 = A B C 0 D 1-0 = Slide 6 / 111 Slide 66 / 111 Subtracting Down Vertical Subtraction - = Click to Return to Table of Contents - = 1-1
Slide 67 / 111 Subtracting Down Match the problems. Slide 68 / 111 Complete the Problems Subtracting Down 6 - = - 1 = 1 - = 0 - = 1-0 6 - - 1 1 8 - - Slide 69 / 111 Subtracting Down 18 Are these the same problem? Slide 70 / 111 Yes No - 1 = 1 1 Slide 71 / 111 Slide 7 / 111 19 Do they represent the same problem? 0 Solve the problem. What is the answer? Yes No - =1 A B 1 C D 0
Slide 7 / 111 1 What is the answer to the problem? Slide 7 / 111 What is the answer to this problem? A B C D 1 - A 0 B 1 C D Slide 7 / 111 Slide 76 / 111 Is the answer to this problem? Yes No -0 Number Facts to Click to Return to Table of Contents Slide 77 / 111 Slide 78 / 111 Fluently Subtract The following pages provide fluency practice for subtraction within. click click Can You Subtract? click 1-0 1 click click -0 click 1 click click
Slide 79 / 111 Slide 80 / 111 And the answer is? 1-0 -0 Subtraction Facts Slide 81 / 111 Slide 8 / 111 Do not use counters. What is the answer? Do not use counters. What is the answer? A 1 B C D -0 A 1 B C D Slide 8 / 111 6 Do not use counters. What is the answer? Slide 8 / 111 7 Do not use counters. What is the answer? A 1 B C D A 1 B C D -
Slide 8 / 111 Slide 86 / 111 8 Do not use counters. What is the answer? A 1 B C D Addition & Subtraction Games Click to Return to Table of Contents Slide 87 / 111 Slide 88 / 111 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. 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, +, +,,, 0 Slide 89 / 111 Kangaroo Number Line Subtraction/Addition 0 1 6 7 8 9 10 Roll dice and move the kangaroo along the number line. Children can follow along with number lines and markers at seats. Slide 90 / 111 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.
Slide 91 / 111 Slide 9 / 111 Player One Plus or Minus Game Player Two 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. Slide 9 / 111 Slide 9 / 111 Addition/Subtraction Candy Game Addition/Subtraction Dinosaur Race Game Team A Team B Slide 9 / 111 Addition/Subtraction Bumble Bee Game Slide 96 / 111 Addition/Subtraction Fairy Tale Game Help the b porridge. forward o on the plu +
Slide 97 / 111 Slide 98 / 111 Addition & Subtraction Problem Solving Click to Return to Table of Contents 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. Slide 99 / 111 Problem Solving Choosing the Operation Slide 100 / 111 Problem Solving Choosing the Operation + 7 +1 Slide 101 / 111 Slide 10 / 111
Slide 10 / 111 Problem Solving Choosing the Operation Slide 10 / 111 Create your own problem. Is this an addition or subtraction story? Do we use + or - symbol? Slide 10 / 111 Slide 106 / 111 Create your own problem. Is this an addition or subtraction story? Do we use + or - symbol? 9 What problem matches the story? A -= B += C +=8 D -=1 There are apples. Joe eats. How many are left? Slide 107 / 111 Slide 108 / 111 0 Bonnie finds shells. Then she finds more. How many does she have now? Do we add or subtract? 1 Dom had cars. He loses one. How many does he have now? A + B - A + B -
Slide 109 / 111 Slide 110 / 111 Which equation matches the story problem? Find the equation that matches the story problem. A +=6 B 6-= Ryan finds frogs. Ethan finds frogs. How many frogs do they have altogether? A +=8 B +=7 Justin shoots 7 basketballs. go in the net. How many missed the net? C +=6 C 7-= D 6-6=0 D 8-= Slide 111 / 111 Let's Get the Beat of Subtraction