2. Single Digit Whole Number Subtraction FlashCards

3. The Whole Numbers are the natural numbers (1, 2, 3, …), and the number zero (0).

4. When we subtract zero (0) from any number, the result (difference) is the number that zero was subtracted from. The rule reads: a – 0 = a ( But be careful…0 – a = -a ) So 7 – 0 = 7

5. When we subtract any number from itself the result (difference) is zero. The rule reads: a – a = 0 So 5 – 5 = 0

6. When we subtract two numbers, the order does matter. There is no rule (of Commutivity for Subtraction) because: a - b  b - a You can see with this example… 8 - 5 = 3, but 5 - 8 = -3.

7. You may have remembered being asked to memorize whole number subtraction facts in grade school. To perform a subtraction problem it is helpful to see the relationship to its related addition problem.

8. For instance, in order to subtract 2 from 9; that is perform the following subtraction problem: 9 – 2 = ? It helps if you know that : 2 + ? = 9 is the related addition problem.

9. So since : 2 + 7 = 9 or 7 + 2 = 9, then : 9 – 2 = 7 And also : 9 – 7 = 2

10. Fix Subtraction Flash Cards So that you use addition table “inside out” like w/ division flash cards OK?

11. The next 55 slides will be randomly mixed “flash cards” for subtracting single digit whole numbers, where the difference is still a whole number (no negative numbers yet…) which drill & practice the facts from the subtraction problems you have been exposed to over the years. The answers will be revealed (UPSIDE DOWN) two seconds after the “flash card” pops up Use the “NEXT” button (below on the right) to get more “flash cards”. If you wish to end the session, use the “END” button (below on the left)

12. 7 - 4 = ?

13. 8 - 0 = ?

14. 8 - 2 = ?

15. 5 - 1 = ?

16. 9 - 6 = ?

17. 7 - 6 = ?

18. 4 - 2 = ?

19. 9 - 3 = ?

20. 5 - 4 = ?

21. 3 - 0 = ?

22. 9 - 5 = ?

23. 6 - 6 = ?

24. 8 - 4 = ?

25. 2 - 1 = ?

26. 7 - 7 = ?

27. 6 - 2 = ?

28. 4 - 0 = ?

29. 9 - 4 = ?

30. 6 - 1 = ?

31. 6 - 5 = ?

32. 9 - 8 = ?

33. 5 - 0 = ?

34. 3 - 2 = ?

35. 6 - 3 = ?

36. 7 - 2 = ?

37. 1 - 0 = ?

38. 4 - 3 = ?

39. 9 - 7 = ?

40. 2 - 0 = ?

41. 8 - 6 = ?

42. 9 - 1 = ?

43. 7 - 3 = ?

44. 2 - 2 = ?

45. 8 - 7 = ?

46. 7 - 0 = ?

47. 7 - 5 = ?

48. 3 - 3 = ?

49. 8 - 5 = ?

50. 6 - 0 = ?

51. 3 - 1 = ?

52. 0 - 0 = ?

53. 7 - 1 = ?

54. 9 - 2 = ?

55. 4 - 4 = ?

56. 9 - 0 = ?

57. 8 - 3 = ?

58. 8 - 1 = ?

59. 9 - 9 = ?

60. 6 - 4 = ?

61. 1 - 1 = ?

62. 5 - 3 = ?

63. 8 - 8 = ?

64. 5 - 2 = ?

65. 4 - 1 = ?

66. 5 - 5 = ?

67. Wow! You actually reviewed every one of those 55 subtraction problem flash cards… Good for you! Come back anytime to review these subtraction subtraction facts, if you begin to feel rusty, OK? Close the document by first pushing the “ESC” (Escape) button in the top left corner of your keyboard, and then click on the red in the top right corner of the dialog box.

68. Thank you for reviewing your subtraction facts… May the force be with you… Close the document by first pushing the “ESC” (Escape) button in the top left corner of your keyboard, and then click on the red in the top right corner of the dialog box.