Counting Backward/Forward

_ _ 3

1, 2

_ _ 4

2, 3

_ _ 5

3, 4

_ _ 6

4, 5

_ _ 7

5, 6

_ _ 8

6, 7

_ _ 9

7, 8

_ _ 10

8, 9

_ _ 11

9, 10

_ _ 12

10, 11

_ _ 13

11, 12

_ _ 14

12, 13

_ _ 15

13, 14

_ _ 16

14, 15

_ _ 17

15, 16

_ _ 18

16, 17

_ _ 19

17, 18

_ _ 20

18, 19

_ 4 5

3

_ 5 6

4

_ 6 7

5

_ 7 8

6

_ 8 9

7

_ 9 10

8

_ 10 11

9

_ 11 12

10

_ 12 13

11

_ 13 14

12

_ 14 15

13

_ 15 16

14

_ 16 17

15

_ 17 18

16

_ 18 19

17

_ 19 20

18

1 _ 3

2

2 _ 4

3

3 _ 5

4

4 _ 6

5

5 _ 7

6

6 _ 8

7

7 _ 9

8

8 _ 10

9

9 _ 11

10

10 _ 12

11

11 _ 13

12

12 _ 14

13

13 _ 15

14

14 _ 16

15

15 _ 17

16

16 _ 18

17

17 _ 19

18

18 _ 20

19

1, 2, _

3

2, 3, _

4

3, 4, _

5

4, 5, _

6

5, 6, _

7

6, 7, _

8

7, 8, _

9

8, 9, _

10

9, 10, _

11

10, 11, _

12

11, 12, _

13

12, 13, _

14

13, 14, _

15

14, 15, _

16

15, 16, _

17

16, 17, _

18

17, 18, _

19

18, 19, _

20