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2. 1st Grade Subtraction to 20 www.njctl.org 2013-03-28

3. Setting the PowerPoint View Use Normal View for the Interactive Elements To use the interactive elements in this presentation, do not select the Slide Show view. Instead, select Normal view and follow these steps to set the view as large as possible: On the View menu, select Normal. Close the Slides tab on the left. In the upper right corner next to the Help button, click the ^ to minimize the ribbon at the top of the screen. On the View menu, confirm that Ruler is deselected. On the View tab, click Fit to Window. Use Slide Show View to Administer Assessment Items To administer the numbered assessment items in this presentation, use the Slide Show view. (See Slide 23 for an example.)

4. Table of Contents click on the topic to go to that section - Subtraction Models with Cubes - Real World Subtraction with Counters - Subtraction Sentences - Subtraction on a Number Line - Subtraction on a Number Grid - Number Stories - Subtracting Zero - Subtracting One - Subtracting Ten - Patterns when Subtracting Ten - Subtracting All - Fact Families - Fact Triangles - Missing Number Part 2 - Missing Number - Get to Ten

5. Real World Subtraction with Counters Click to return to Table of Contents

6. When we subtract, we find the difference between two numbers.

7. Four turkeys are on the fence. Two fly away. How many turkeys left?

8. Jen has six potatoes on her plate. Three potatoes roll off. How many potatoes are left?

9. We can use counters to help us solve subtraction problems. 8 apple pies 2 pies are eaten ______ pies left

10. Let's Practice 10 balloons 5 blow away ______ balloons are left

11. Let's Practice 3 leaves on a tree 3 leaves fall off ______ leaves left

12. Let's Practice 6 take away 1 _____ left

13. Let's Practice 8 take away 3_____ left

14. Let's Practice 9 take away 5left _____

15. Subtraction Models with Cubes Click to return to Table of Contents

16. 6 dogs 3 ran away How many dogs are left?

17. Let's show it with counters 6 3 ________ dogs ran away dogs left

18. We can also use connecting cubes to help us subtract. Each cube represents an object. To show subtraction, remove the amount taken away. 2 1 ______ blue birds flies away birds left

19. Use connecting cubes to help you solve these problems. 8 flies, a frog eats 2. How many flies left? 5 cars, 3 drive away. How many cars left? 7 cookies, Pam eats 4. How many cookies left?

20. We can draw squares to represent connecting cubes as well. 4 crows 4 fly away _______ crows left

21. 5 apples 3 are rotten _____ apples left 7 rakes 2 break _____ rakes left

22. 11 turkeys 4 hide in a tree _____ turkeys left 8 leaves on a tree 6 fall off _____ leaves left

23. 1 7 dogs are outside and 3 run away. There are 10 dogs in all. Yes No

24. 2 3 cats and 3 run away. _____ cats left. A 5 B 6 C 0

25. 3 4 rakes and 2 break. _____ rakes left. A 2 B 6 C 8

26. 4 3 pumpkins and 2 roll away ____ pumpkins left.

27. 5 8 hats and 4 blow away. _____ hats left.

28. Subtraction Sentences Click to return to Table of Contents

29. 3 - 2 = 1= 1

30. 9 - 5 4

31. 6 = 5

32. 2 - 2 0

33. 9 - 3 = 6

34. 8 - 2 6

36. 6 Which subtraction sentence matches this story: Six kids are playing. Four kids go home. Now there are two kids left. A 6 – 2 = 4 B 6 – 4 = 10 C 6 – 4 = 2

37. 7 Which subtraction sentence matches this story: Five pumpkins are on the table. The farmer sells two. There are three pumpkins left. A 5 – 3 = 2 B 5 – 2 = 3 C 5 – 2 = 7

38. 8 Which subtraction sentence matches this story: Six balloons are tied on the fence. Five pop. 1 Balloon is left. A 6 – 5 = 1 B 6 – 1 = 5 C 6 – 5 = 2

39. 9 Which subtraction sentence matches this story: Ten chickens are at the farm. Four fly away. How many chickens are left? A 10 – 6 = 4 B 10 – 4 = 6 C 10 – 4 = 5

40. 10 Which subtraction sentence matches this story: Thirteen pieces of candy are on the table. Jen eats 5 pieces. There are 8 pieces left. A 13 – 8 = 5 B 13 – 5 = 7 C 13 – 5 = 8

41. Number Stories Click to return to Table of Contents

42. If you had 14 crackers in your lunch and you ate five of them, how many would you have left?

43. What is the difference between how many buttons you have on and how many your teacher has? Try this one. What is the difference between how many buttons you have on and how many your friend has?

44. 10 - 7 = Make up your own story for this.

45. 6 - 3 Make up a different story for this one.

46. Completion Models Your pencil box has many different kinds of pencils. Of your 10 pencils, 3 of them are mechanical pencils. How many are not mechanical pencils?

47. Can you make up a story for this number sentence? 12 - ? = 6 For help in making the story, slide box down to reveal hint. Hint 1: What can you have 12 of? Hint 2: How are 6 of those 12 that are special in some way? Hint 3: How many are not special in that way?

48. Comparison Model If your friend is two months older than you and you were born in September, what month was he or she born?

49. 1) With a partner who is your same age, find out what month they were born. 2) Find out how many months older you are or they are from the other. 3) Find a way to turn that into a number story. Slide box to reveal hint on turning it into a number story. Hint: (oldest person) is _____months older than (youngest person). If (youngest person) was born in ___________, what month was (oldest person) born in. Student Activity

50. Whole/Part/Part Model I have 10 cookies and three of them are chocolate chip. How many are not chocolate chip? There are 12 pieces of fruit in a bowl. Five of them are apples. How many are not apples?

51. 11 If you had fifteen grapes for lunch and you ate 9 of them, how many did you have left? A 4 B 5 C 6 D 7

52. 12 If your family had $20 to spend on dinner and they spent $14, how much did they have left?

53. 13 The colored pencil box folds 12 pencils. If you borrowed some and now there are 8 left in the box, how many did you borrow? A 4 B 5 C 6 D 7

54. 14 If your cousin was 12 years older than you, and you are 6. how old is your cousin?

55. 15 You see 15cookies in a box. Nine of them are chocolate chip. How many are not chocolate chip? A 6 B 7 C 8 D 9

56. 16 In a collection of 10 rocks, three are pure white. How many are not pure white?

57. 17 For a party of 14 people, you need to set up six small chairs for the kids. How many do you need for the rest of the people? A 5 B 6 C 7 D 8

58. 18 Children typically have 20 teeth until they start falling out. If you had three out of your twenty fall out so far, how many do you have left??

59. Subtraction on a Number Line Click to return to Table of Contents

60. We can use a number line to find the difference between two numbers (subtract). 5 - 3 = _____ The first number in the subtraction sentence tells us where to start. The second number tells us how many jumps to take back. The difference (answer) of the two numbers is where we end. Starting number Number of jumps Where did you end?

61. Sometimes it helps to circle the first number to help us remember where to start. 5 - 3 = _____ Don't forget to start counting after you jump!! 1 2 3

62. What number should we circle? How many jumps will we take? Where did we land? 9 - 4 = _____

63. What number should we circle? How many jumps will we take? Where did we land? 11 - 8 = _____

64. 19 6 - 1 = 7 Yes No

65. 20 5 - 3 = 2 Yes No

66. 21 3 - 3 = ____ A 6 B 1 C 0

67. 2217 - 2 = _____

68. 2316 - 7 =

69. Click to return to Table of Contents Subtraction on a Number Grid

70. We can use a number grid to help us subtract larger numbers

71. The first number in the subtraction sentence tell us where to start. The second number tells us how many jumps to take back. The difference between the two numbers (answer) is where we end. 12 - 7 = ____

72. 19 - 6 = ____ 6 5 4 3 2 1

73. Look at the subtraction sentence. Where will we start on the number grid? How many jumps will we take? 14 - 3 = ____ ** Just like on a number line, don't count until you jump **

74. 14 - 4 = ____ What should we do when we get to the last number in a row?

75. 17 - 8 = ____

76. 20 - 5 = ____

77. 7 - 6 = ____

78. 24 11 - 6 = 5 True False

79. 25 6 – 4 = A 1 B 2 C 10

80. 26 7 - 7 = A 0 B 14 C 1

81. 27 18 - 9 =

82. 2813 - 8 =

83. Click to return to Table of Contents Subtracting Zero

84. Amy had 8 pieces of candy. She decides to eat 0 pieces. How many pieces of candy are left?

85. Let's work through it! What do we need to find out? What information do we know? How can we show this problem with cubes?

86. Any time we subtract zero from a number, the answer is the same as the first number. 4 - 0 = 4 13 - 0 = 13 18 - 0 = 18

87. How would we show taking away zero with counter? 6 - 0 =

88. How would we show subtracting zero with cubes? 9 - 0 =

89. Remember since we are not taking away any cubes or counters, the answer is the same as the first number. 13 - 0 = 13

90. 19 - 0 = ______ 11 - 0 = ______ 6 - 0 = ______ 8 - 0 = ______ 14 - 0 = ______ Find the difference

91. 299 - 0 = 9 True False

92. 30 4 - 0 = ______ A 40 B 4 C 0

93. 31 6 - 0 = ____

94. 32 10 - 0 = _____

95. 3317 - 0 = _____

96. Click to return to Table of Contents Subtracting All

97. When the starting number and the number taken away are the same, you are subtracting all. 17 - 17 = 0 9 - 9 = 0 Same

98. When subtracting all, the difference is always 0. 6 - 6 = 0 12 - 12 = 0

99. 8 - 8 = _____ Cover the counters to show how many you will take away.

100. 12 - 12 = ___ Cover the counters to show how many you will take away.

101. 17 - 17 = ___ Cover the counters to show how many you will take away.

102. 2 - 2 = ___ Cover the counters to show how many you will take away.

103. 5 - 5 = ___

104. 14 - 14 = ____

105. 11 - 11 = ____

106. 16 - 16 = ____

107. 3412 - 12 = _____

108. 354 - 4 = _____

109. 367 - 7 = _____

110. Subtract Zero - or - Subtract All Fill in more examples in the chart. Subtract Zero Subtract All 7 - 0 = 7 16 - 16 = 0 12 - 0 =12 6 - 6 = 0

111. Click to return to Table of Contents Subtracting One

112. When we subtract one, we count back one number. 4 - 1 = 3 3 is one less than 4

113. Try to picture a number line in your head. Find the first number, then take just one jump back. 4 - 1 = 3 Three is one less than four

114. Try to picture a number line in your head. 7 - 1 = __ What number will you start at? How many jumps will you take?

115. 5 - 1 = 12 - 1 = Let's Practice ___

116. We can use cubes to help us subtract one. To show - 1, take away one cube. 3 - 1 =

117. Your mom gave you five cookies. Then she took one away. How many are left? 5 - 1 =

118. You picked 9 flowers. You gave one away. How many are left? 9 - 1 =

119. Your sister has 12 crayons. She gave one away to you. How many are left? 12 - 1 =

120. 37 14 - 1 =

121. 38 17 - 1 =

122. 394 - 1 =

123. 4018 - 1 =

124. 415 - 1 =

125. Click to return to Table of Contents Subtracting Ten

126. Subtracting 10 is very easy when using a number grid. Find the first number on the number grid and move up one box.

127. 14 - 10 = 4

128. 16 - 10 = Let's Practice Finding the Difference

129. 12 - 10 = Let's Practice Finding the Difference What number would you circle?

130. 18 - 10 = Let's Practice Finding the Difference What number would you circle?

131. 10 - 10 = Let's Practice Finding the Difference What number would you circle?

132. 42Does 15 - 10 = 5 Yes No

133. 43 19 - 10 = 19 True False

134. 4418 - 10 = A 18 B 81 C 8

135. 45 16 - 10 =

136. 46 14 - 10 =

137. Click to return to Table of Contents Patterns when Subtracting Ten

138. 16 - 10 When subtracting 10 from a "teen", the tens place is always 0 and the ones place stays the same. 1 went down one number to 0 06

139. 12 - 10 2 14 - 10 4 19 - 10 9 17 - 10 7

140. Let's Practice _____ 15 - 10 = 16 - 10 = 18 - 10 = 11 - 10 =

141. 4714 - 10 = 4 Yes No

142. 48 16 - 10 = ____ A 6 B 16 C 61

143. 4912 - 10 = 3 True False

144. 50 13 - 10 = ____

145. 5118 - 10 = ____

146. Click to return to Table of Contents Fact Families

147. A fact family is made up of three numbers. Just like in a real family, the numbers are related. We can use the three numbers to make 4 different number sentences (2 addition and 2 subtraction).

148. A fact family is like a family of bears. There is a daddy bear, a mommy bear, and a baby bear. 9, 7, 2 There is the biggest number like the daddy bear. There is the middle number like the mommy bear. And there is the smallest number like the baby bear. 9 7 2

149. 9 - 2 = 7 9 - 7 = 2 This is what a fact family looks like 2 + 7 = 9 7 + 2 = 9 9, 7, 2

150. The number sentences can only be made with the numbers in the fact family. 9, 7, 2 2 + 7 = 9 7 + 2 = 9 9 – 2 = 7 9 – 7 = 2

151. When making addition sentences the daddy number is always the sum. The two addition sentences are also turn around facts. 2 + 7 = 9 7 + 2 = 9

152. When making subtraction sentences the daddy number is always first since we cannot subtract a bigger number from a smaller number. 9 – 2 = 7 9 – 7 = 2

153. 9, 10, 1

154. 12, 4, 8

155. 16, 7, 9

156. 5, 2, 7

157. 52 Which addition sentence belongs to this fact family? 6, 7, 1 A 6 + 2 = 8 B 6 + 1 = 7

158. 53Which subtraction sentence belongs to this fact family? 4 + 1 = 5 1 + 4 = 5 5 - 4 = 1 ? A 5 – 1 = 4 B 5 – 1 = 3 C 4 – 1 = 5

159. 54 8 + 7 = 15 ? 15 - 7 = 8 15 - 8 = 7 Which addition sentence belongs to this fact family? A 7 + 7 = 15 B 7 + 8 = 15 C 15 + 7 = 8

160. 55 Which subtraction sentence belongs to this fact family? 9, 7, 2 A 9 – 2 = 7 B 7 – 2 = 9 C 2 – 9 = 7

161. 56 Which number is missing from this family? 12, 4, ____ A 5 B 7 C 8

162. Click to return to Table of Contents Fact Families with Dominoes

163. How many dots are there on the left? How many dots are there on the right? How many dots in all?,,

164. How many dots are there on the left? How many dots are there on the right? How many dots in all?,,

165. Each domino can represent three different numbers. We can use these three numbers to write fact families. 5, 6, 11 5 + 6 = 11 6 + 5 = 11 11 - 5 = 6 11 - 6 = 5

166. Numbers: _______, _______, _______ Fact Family: ____ + ____ = ____ ____ - ____ = ____

167. Numbers: _______, _______, _______ Fact Family: ____ + ____ = ____ ____ - ____ = ____

168. Numbers: _______, _______, _______ Fact Family: ____ + ____ = ____ ____ - ____ = ____

169. Numbers: _______, _______, _______ Fact Family: ____ + ____ = ____ ____ - ____ = ____

170. Numbers: _______, _______, _______ Fact Family: ____ + ____ = ____ ____ - ____ = ____

171. Fact Family Domino Grab - Pick one domino from the pile. - Work with your partner to fill out the fact family chart. - Continue until your sheet is complete.

172. 57 Which addition sentence belongs to this family? A 4 + 2 = 6 B 4 + 6 = 10 C 2 + 6 = 4

173. 58 Which subtraction sentence belongs to this family? A 3 – 2 = 5 B 5 – 3 = 2 C 2 – 3 = 1

174. 59Which other number belongs to this fact family? ____, 1, 6

175. 60Which other number belongs to this fact family? 6, 2, ___

176. 61 Which other number belongs to this fact family? 5, ___, 9

177. Click to return to Table of Contents Fact Triangles

178. Click for fact triangles web site

179. +, - 10 6 4 This is called a fact triangle Fact triangles helps us practice fact families

180. Subtract 6 from 10 10 - 6 = 4 Subtract 4 from 10 10 - 4 = 6 Add them together 6 + 4 = 10 4 + 6 = 10 +, - 10 6 4 How can we use the other two numbers to get to 10? How can we use the other two numbers to get to 6? How can we use the other two numbers to get to 4?

181. +, - 5 2 7 How can we get to 7? ______ + ______ = ______ How can we get to 5? ______ - ______ = ______ How can we get to 2? ______ - ______ = ______ What does the dot on a fact triangle tell us?

182. +, - 3 1 4 How can we get to 4? ______ + ______ = ______ How can we get to 3? ______ - ______ = ______ How can we get to 1? ______ - ______ = ______

183. +, - 6 9 15 How can we get to 15? ______ + ______ = ______ How can we get to 6? ______ - ______ = ______ How can we get to 9? ______ - ______ = ______

184. Get to the Covered Number +, - 9 4 13 Use the star to cover one number. Then have your partner write one fact on their slate that has the covered number as the answer. _______ ________ = ________

185. Let's try it again! +, - 12 5 17 _______ ________ = ________

186. 62 What addition facts goes with this fact triangle? 3 5 +, - 2 A 2 + 3 = 5 B 5 + 3 = 2 C 5 + 2 = 3

187. 63 What subtraction facts goes with this fact triangle? A 6 – 1 = 1 B 11 – 5 = 6 C 5 + 6 = 11

188. 64 What number is missing? 4 12 +, - ? A 3 B 8 C 2

189. 65 What number is missing? 31 +, - ?

190. 66 What number is missing? 6 8 +, - ?

191. Click to return to Table of Contents Missing Number

192. There are times when a subtraction sentence will be missing the second number. 6 - ___ = 4 Remember that the numbers on each side of the = must equal the same amount. So since 4 is on the right we need to find out what we can take away from 6 on the left to get to 4.

193. 6 - ___ = 4 To find the missing number put the answer in your head and count up on your fingers to the other given number. 4 5 6 Stop at 6 since the other given number is 6 6 - ___ = 4 Since we put up two fingers to get to 6, the missing number is 2 2

194. 12 - ___ = 8 What number should we put in our head? What number should we count up to? 8

195. 14 - ___ = 9 What number should we put in our head? What number should we count up to? 9

196. 16 - ___ = 9 What number should we put in our head? What number should we count up to? 9 click

197. 12 - ___ = 4 What number should we put in our head? What number should we count up to? 4

198. 8 - ____ = 2 What number should we put in our head? What number should we count up to? 2

199. 13 - ___ = 9 What number should we put in our head? What number should we count up to? 9

200. Let's Practice 9 – ___ = 8 11 – ___ = 9 12 – ___ = 6 13 – ___ = 10 12 – ___ = 7

201. 67 10 - _____ = 8 A 2 B 10 C 3

202. 68 9 - ___ = 3 A 2 B 5 C 6

203. 6917 - ___ = 12

204. 70 14 - ____ = 7

205. 71 8 - ___ = 8

206. Click to return to Table of Contents Missing Number Part 2

207. There are times when a subtraction sentence will be missing the first number. ____ - 6 = 9 To find the missing first number, we need to add the difference (answer) and the other given number. +

208. _____ - 6 = 9 Put the bigger number in your head and the other number on your fingers. Then start at the bigger number and count up on your fingers. 9 10 Stop at 15 since there are no more fingers to count Since we stopped counting at 15, the missing number is 15 _____ - 6 = 9 15 11 12 13 14 15

209. ____ - 3 = 4 What number should we put in our head? How many fingers should we put up? 4

210. ____ - 5 = 11 What number should we put in our head? How many fingers should we put up? 11

211. ____ - 9 = 4 What number should we put in our head? How many fingers should we put up? 9

212. ____ - 8 = 2 What number should we put in our head? How many fingers should we put up? 8

213. ____ - 12 = 8 What number should we put in our head? How many fingers should we put up? 12

214. Fill in the Missing Number _____ - 8 = 9 _____ - 3 = 3 _____ - 7 = 2 _____ - 1 = 4 _____ - 12 =7 _____ - 7 = 5 _____ - 9 = 6 _____ - 0 = 2

215. 72 What is the missing number? ____ - 4 = 6 A 11 B 10 C 9

216. 73 What is the missing number? ____ - 8 = 8 A 16 B 5 C 18

217. 74 What is the missing number? ____ - 4 = 5

218. 75What is the missing number? ____ - 3 = 8

219. 76 What is the missing number? ____ - 3 = 3

220. Click to return to Table of Contents Get to Ten

221. Sometimes we may need to break apart a number into 2 smaller numbers to help solve a subtraction sentence. One way to break apart a number is to figure out what we can take away from the first number to make 10.

222. 12 - 4 = ___ B A

223. 16 - 7 = ___ B A

224. 15 - 8 = ___ B A

225. 14 - 5 = ? What can we take away from 14 to make 10? 4 – 1 = 14 -

226. 12- 3 = ? What can we take away from 12 to make 10? 2 – 1 This is what you Are thinking in Your head = 12 - 3

227. 17- 9 = ? What can we take away from 17 to make 10? 7 – 2 This is what you Are thinking in your head = 17 - 9

228. 13- 7 = ? What can we take away from 13 to make 10? 3 – 4 this is what you Are thinking in Your head = 13 - 7

229. 15- 9 = ? What can we take away from 15 to make 10? 5 – 4 This is what you Are thinking in Your head =15 -9

230. 77 What sentence shows a breakdown of: 11 - 2 = 9 A 11 – 1 – 1 = 9 B 11 – 3 – 2 = 9 C 11 – 2 – 1 = 9

231. 78 What sentence shows a breakdown of: 13 - 5 = 8 A 13 – 3 – 1 = 8 B 13 – 3 – 2 = 8 C 13 – 2 – 1 = 8

232. 79 What sentence shows a breakdown of: 15 - 6 = 9 A 15 – 5 – 0 = 9 B 15 – 5 – 2 = 9 C 15 – 5 – 1 = 9

233. 14 - 6 =80

234. 16 - 9 = 81