Complete number sentences involving addition and subtraction by calculating missing numbers, eg find the missing numbers: ( ) + 55 = 88, ( ) - 15 = 19
| 1. | Number Detectives: 10 + ? = 34 | |
| 2. | Make 19: 8+6+? | |
| 3. | Make 18: 4+11+? | |
| 4. | Make 20: 9+11+? | |
| 5. | Make 20: 9+6+? | |
| 6. | Adding tens: 26 + ? = 36 | |
| 7. | Adding tens: 46 + ? = 56 | |
| 8. | Adding tens: 64 + ? = 94 | |
| 9. | Adding tens: ?+ 36 = 66 | |
| 10. | Adding tens: ?+ 73 = 83 | |
| 11. | Adding tens: ?+ 46 = 86 | |
| 12. | Number detectives: Mysteries of 15 | |
| 13. | Number detectives: Mysteries of 16 | |
| 14. | Number detectives: Mysteries of 13 | |
| 15. | Number detectives: Mysteries of 17 | |
| 16. | Number detectives: Mysteries of 14 | |
| 17. | Make 30: 20 + 7 + ? = 30 | |
| 18. | Adding tens: 120 + ? = 140; 120 + 50 = ? | |
| 19. | Adding tens: 24 + ? = 64, 24 + 50 = ? | |
| 20. | Adding tens: 145 + ? = 155, 145 + 30 = ? | |
| 21. | Adding tens: 57 + ? = 97, 57 + 20 = ? | |
| 22. | Adding tens: 138 + ? = 178, 178 + 20 = ? | |
| 23. | Number Detectives: ? + 7 = 30 | |
| 24. | Number Detectives: ? + 24 = 30 | |
| 25. | Number Detectives: 22 + ? = 30 | |
| 26. | Number Detectives: 21 + ? = 30 | |
| 27. | Number detectives: 30+?, 50+?, 60+? =100 | |
| 28. | Number detectives: 80+?, 90+?, 40+?=100 | |
| 29. | Number detectives: 10+?, 70+?, 50+?=100 | |
| 30. | Number detectives: 25+?, 35+?, 55+? =100 | |
| 31. | Number detectives: 5+?, 45+?, 15+?=100 | |
| 32. | Addition Chains: 2 + 4 + 3 + 10, 12 + 1 + 2 + 7 | |
| 33. | Addition Chains: 3 + 2 + 4 + 8, 4 + 3 + 7 + 4 | |
| 34. | 100 Zone: 93 + 10, 94 + 10, 96 + 10 | |
| 35. | 100 Zone: 90 + 10, 92 + 10, 97 + 10 | |
| 36. | 100 Zone: 95 + 10,10 + 95, 105 - 10 | |
| 37. | 100 Zone: 98 + 10,10 + 98, 108 - 10 | |
| 38. | 100 Zone: 99 + 10,109 - 10, 10 + 99 | |
| 39. | Number detectives: ? + 9 = 49 | |
| 40. | Number detectives: ? + 11 = 53 | |
| 41. | Number detectives: 35+? = 46 | |
| 42. | N/D Mysteries of 40! 34+? 30+? 38+?=40 | |
| 43. | N/D Mysteries of 40! 31+? 36+? 30+?=40 | |
| 44. | N/D Mysteries of 40! 33+? 37+? 32+?=40 | |
| 45. | N/D Mysteries of 40! 32+? 39+? 34+?=40 | |
| 46. | N/D Mysteries of 40! 31+? 35+? 37+?=40 | |
| 47. | 100 Zone: 70 + 40 = ? 90 + ? = 110, ? + 80 = 110 | |
| 48. | 100 Zone: 60 + 80 = ? 90 + ? = 140, ? + 100 = 140 | |
| 49. | 100 Zone: 70 + 80 = ? 100 + ? = 150, ? + 70 = 150 | |
| 50. | 100 Zone: 90 + 70 = ? 80 + ? = 160, ? + 60 = 160 | |
| 51. | 100 Zone: 95+7=? 101-?=99 ?+6=103 | |
| 52. | 100 Zone: 95+6=? 103-?=99 ?+6=104 | |
| 53. | 100 Zone: 98+7=? 105-?=98 ?+6=105 | |
| 54. | 100 Zone: 98+6=? 102-?=98 ?+5=103 | |
| 55. | 100 Zone: 98+3=? 101-?=97 ?+5=102 | |
| 56. | Number detectives *+109 = 113 | |
| 57. | Number detectives *+4 = 103 | |
| 58. | Number detectives *+5 = 103 | |
| 59. | Number detectives 485+*= 493 | |
| 60. | Number detectives 515+*= 523 | |
| 61. | Number detectives 95+*=101 | |
| 62. | Number detectives 97+*=103 | |
| 63. | Number Detectives: 100 Pairs ? + 79 = 100 | |
| 64. | Number Detectives: 100 Pairs ? + 51 = 100 | |
| 65. | Number Detectives: 100 Pairs 88 + ? = 100 | |
| 66. | Adding Tens 167 + * = 197 | |
| 67. | Add Hundreds: 600+ * = 946 | |
| 68. | Add Hundreds: 200+ * = 580 | |
| 69. | Add Hundreds: 400+ * = 963 | |
| 70. | Add Hundreds: 100+ * = 319 | |
| 71. | Add Hundreds: 300+ * = 565 | |
| 72. | Adding Tens: * + 726 = 786 | |
| 73. | Adding Tens: * + 314 = 394 | |
| 74. | Add Hundreds: * + 300 = 330 | |
| 75. | Add Hundreds: * + 200 = 241 | |
| 76. | Add Hundreds: * + 800 = 819 | |
| 77. | Add Hundreds: * + 300 = 345 | |
| 78. | Add Hundreds: * + 200 = 295 | |
| 79. | Number Detectives: 100 Pairs 85 + ?, 75 + ?, 45 +?= 100 | |
| 80. | Mystery number: ?+7=252 | |
| 81. | Mystery number: ?+6=174 | |
| 82. | Mystery number: ?+7=451 | |
| 83. | Mystery number: ?+6=512 | |
| 84. | Mystery number: ?+6+163 | |
| 85. | Mystery number: 157+?=163 | |
| 86. | Mystery number: 133+?=146 | |
| 87. | Mystery number: 212+?=224 | |
| 88. | Mystery number: 106+?=118 | |
| 89. | Mystery number: 106+?=118 | |
| 90. | Adding Tens: 142+?=182 | |
| 91. | Adding Tens: 30+?=574 | |
| 92. | Adding Tens: ?+30=492 | |
| 93. | Mysteries of 30!: 20+?, 15+?, 5+? | |
| 94. | Mysteries of 30!: 19+?, 10+?, 16+? | |
| 95. | Mysteries of 30!: 12+?, 13+?, 14+? | |
| 96. | Mysteries of 30!: 9+?, 5+?, 7+? | |
| 97. | Mysteries of 30!: 26+?, 28+?, 22+? | |
| 98. | 100 zone: 796+7,794+8,799+6 | |
| 99. | 100 zone: 593+7,594+8,596+5 | |
| 100. | 100 zone: 693+9,695+8,697+7 | |
| 101. | 100 zone: 392+6,393+7,392+8 | |
| 102. | 100 zone: 196+9,194+7,197+5 | |
| 103. | Number detectives: 30+?, 20+?, 10+?=100 | |
| 104. | Number detectives: 60+?, 50+?, 75+?=100 | |
| 105. | Number detectives: 65+?, 55+?, 85+?=100 | |
| 106. | Number detectives: 82+?, 24+?, 76+?=100 | |
| 107. | Number detectives: 89+?, 21+?, 59+?=100 | |
| 108. | Addition chains 10 multiples | |
| 109. | Addition chains 10 multiples | |
| 110. | Addition chains 10 multiples | |
| 111. | Number detectives: ? - 5 = 10 | |
| 112. | Number detectives: ? - 6 = 3 | |
| 113. | Number detectives: ? - 7 = 2 | |
| 114. | Number detectives: ? - 7 = 6 | |
| 115. | Number detectives: ? - 8 = 4 | |
| 116. | Taking Tens: 90 - ? = 70 | |
| 117. | Subtraction Chain - 22-4=?-3=15 | |
| 118. | Subtraction Chain - ?-8=16-2=14 | |
| 119. | Subtraction Chain - 21-4 =?-1= 16 | |
| 120. | Subtraction Chain - ?-4=19-3=16 | |
| 121. | Mysteries of Fifty: 50-?=42, 50-?=45 | |
| 122. | Mysteries of Fifty: 50-?=48, 50-?=43 | |
| 123. | Mysteries of Fifty: 50-?=44, 50-?=47 | |
| 124. | Mysteries of Forty: 40-?=36, 40-?=31 | |
| 125. | Mysteries of Forty: 40-?=33, 40-?=39 | |
| 126. | Mysteries of Forty: 40-?=35, 40-?=38 | |
| 127. | Mysteries of Thirty: 30-?=29, 30-?=24 | |
| 128. | Mysteries of Thirty: 30-?=21, 30-?=27 | |
| 129. | Mysteries of Thirty: 30-?=26, 30-?=22 | |
| 130. | Number detectives: ? + 23 = 30 | |
| 131. | Number detectives: ? + 18 = 30 | |
| 132. | Number detectives: 30 - ? = 15 | |
| 133. | Number detectives: 30 - ? = 13 | |
| 134. | Number Detectives: ? - 15 = 10 | |
| 135. | Number Detectives: ? - 9 = 21 | |
| 136. | Number Detectives: 30 - ? = 12 | |
| 137. | Number Detectives: 40 - ? = 29 | |
| 138. | Subtracting tens: 88 - ? = 48 | |
| 139. | Subtracting tens: 57 - ? = 27 | |
| 140. | Subtracting tens: 44 - ? = 24 | |
| 141. | Subtracting tens: 86 - ? = 56 | |
| 142. | Subtracting tens: 94 - ? = 24 | |
| 143. | The Mysteries of 40!: 40-?=31, 40-?=33, 40-?=30 | |
| 144. | The Mysteries of 40!: 40-?=51, 40-?=38, 40-?=32 | |
| 145. | The Mysteries of 40!: 40-?=32, 40-?=29, 40-?=37 | |
| 146. | The Mysteries of 40!: 40-?=29, 40-?=38, 40-?=39 | |
| 147. | The Mysteries of 40!: 40-?=30, 40-?=33, 40-?=36 | |
| 148. | The Mysteries of 40!: 40-?=29, 40-?=31, 40-?=33 | |
| 149. | The Mysteries of 40!: 40-?=28, 40-?=32, 40-?=18 | |
| 150. | The Mysteries of 30!: 30-?=26, 30-?=23, 30-?=27 | |
| 151. | The Mysteries of 30!: 30-?=23, 30-?=13, 30-?=3 | |
| 152. | The Mysteries of 30!: 30-?=18, 30-?=15, 30-?=12 | |
| 153. | The Mysteries of 30!: 30-?=14, 30-?=19, 30-?=9 | |
| 154. | Subtraction chains: 30-4-10-8, 30-5-10-7 | |
| 155. | Subtraction chains: 30-8-6-12, 30-6-3-5 | |
| 156. | The Mysteries of 40! 40-14,23,19 | |
| 157. | The Mysteries of 40! 40-8,12,25 | |
| 158. | The Mysteries of 40! 40-20,15,9 | |
| 159. | The Mysteries of 50! 50-35,12,6 | |
| 160. | The Mysteries of 50! 50-16,21,30 | |
| 161. | Subtraction chains: ?-12-7-6=65, ?-11-6-13=50 | |
| 162. | Subtraction chains: ?-11-10-12, ?-8-11-4=7 | |
| 163. | Subtraction chains: ?-10-11-9, 50-12-8-7=23 | |
| 164. | Subtraction chains: ?-11-8-10, ?-9-6-7=34 | |
| 165. | Subtraction chains: ?-7-9-12, ?-12-5-11 | |
| 166. | Take Tens: 67-?=47,430-70=? | |
| 167. | Take Tens: 71-?=21,250-30=? | |
| 168. | Take Tens: 66-?=36,360-80=? | |
| 169. | Take Tens: 94-?=54,740-20=? | |
| 170. | Take Tens: 89-?=19,460-50=? | |
| 171. | Take Tens: 86-?=26,170-40=? | |
| 172. | Take Tens: 45-?=35,580-90=? | |
| 173. | Take Tens: 62-?=22,880-50=? | |
| 174. | Take Tens: 73-?=53,630-90=? | |
| 175. | Take Tens: 98-?=18,920-60=? | |
| 176. | Take tens: 527-?=497 | |
| 177. | Take tens: 849-?=759 | |
| 178. | Take tens: 321-?=251 | |
| 179. | Take tens: 513-?=463 | |
| 180. | Take tens: 655-?=595 | |
| 181. | Mysteries of 100!: 100-?=77, 100-?=60, 100-?=88 | |
| 182. | Mysteries of 100!: 100-?=45, 100-?=28, 100-?=66 | |
| 183. | Mysteries of 100!: 100-?=40, 100-?=75, 100-?=62 | |
| 184. | Mysteries of 100!: 100-?=19, 100-?=80, 100-?=69 | |
| 185. | Mysteries of 100!: 100-?=76, 100-?=65, 100-?=54 | |
| 186. | What Was I Thinking? - find original number after operations | |
| 187. | What Was I Thinking? - find original number after operations | |
| 188. | What Was I Thinking? - find original number after operations | |
| 189. | Number Quest - complete number sentence | |
| 190. | Number Quest - complete number sentence | |
| 191. | Number Quest - complete number sentence | |
| 192. | Number Quest - complete number sentence | |
| 193. | Number Quest - complete number sentence |