Complete number sentences involving one operation of addition or subtraction by calculating the missing number, eg find x so that 5+x=13 or 15?x=9
| 1. | Number Detectives ? + 3 = 6 | |
| 2. | Number Detectives: ? + 5 = 11 | |
| 3. | Number Detectives: 6 + ? = 9 | |
| 4. | Number Detectives: ?+5 = 15 | |
| 5. | Number Detectives: 9 + ? = 15 | |
| 6. | Number Detectives: 8 + ? = 15 | |
| 7. | Number Detectives: ? + 10 = 32 | |
| 8. | Number detectives: 14 - ? = 4 | |
| 9. | Number detectives: 11 - ? = 5 | |
| 10. | Number detectives: 10 - ? = 8 | |
| 11. | Number detectives: 13 - ? = 5 | |
| 12. | Number detectives: 14 - ? = 7 | |
| 13. | Number detectives ? -3 = 11 | |
| 14. | Number detectives 17 -? = 5 | |
| 15. | Take 10: ? - 10 = 60 | |
| 16. | Subtraction chain 20 - 12 = ? - 6 = 2 | |
| 17. | Subtraction Chain - ?-4=21-2=19 | |
| 18. | Subtraction Chain - 27-4=?-6=17 |