1.SUBTRACTION.
I
think I can do these subtractions in ........minutes.
12 - 5 = .........

14 - 7 = .........

18 - 9 = .........

11 - 8 = .........

13 - 4 = .........

15 - 7 = .........

13 - 6 = .........

17 - 9 = .........

11 - 6 = .........

17 - 9 = .........

12 - 8 = .........

11 - 2 = .........

13 - 5 = .........

13 - 8 = .........

11 - 7 = .........

18 - 8 = .........

14 - 5 = .........

20 - 5 = .........

15 - 7 = .........

16 - 8 = .........

13 - 7 = .........

20 - 7 = .........

10 - 7 = .........

12 - 6 = .........

19 - 9 = .........

20 - 8 = .........

12 - 4 = .........

16 - 9 = .........

20 - 9 = .........

13 - 3 = .........

18 - 9 = .........

10 - 5 = .........
 

Actually it took ...........minutes.

 There were ...........right answers.