Level 1

11-0=11

12-0=12

13-0=13

14-0=14

15-0=15

16-0=16

17-0=17

18-0=18

19-0=19

20-0=20

Level 2

11-1=10

12-1=11

13-1=12

14-1=13

15-1=14

16-1=15

17-1=16

18-1=17

19-1=18

20-1=19

Level 3

11-2=9

12-2=10

13-2=11

14-2=12

15-2=13

16-2=14

17-2=15

18-2=16

19-2=17

20-2=18

Level 4

11-3=8

12-3=9

13-3=10

14-3=11

15-3=12

16-3=13

17-3=14

18-3=15

19-3=16

20-3=17

Level 5

11-4=7

12-4=8

13-4=9

14-4=10

15-4=11

16-4=12

17-4=13

18-4=14

19-4=15

20-4=16

Level 6

11-5=6

12-5=7

13-5=8

14-5=9

15-5=10

16-5=11

17-5=12

18-5=13

19-5=14

20-5=15

Level 7       

11-6=5

12-6=6

13-6=7

14-6=8

15-6=9

16-6=10

17-6=11

18-6=12

19-6=13

20-6=14

Level 8

11-7=4

12-7=5

13-7=6

14-7=7

15-7=8

16-7=9

17-17=10

18-7=11

19-7=12

20-7=13

Level 9   

11-8=3

12-8=4

13-8=5

14-8=6

15-8=7

16-8=8

17-8=9

18-8=10

19-8=11

20-8=12

Level 10

11-9=2

12-9=3

13-9=4

14-9=5

15-9=6

16-9=7

17-9=8

18-9=9

19-9=10

20-9=11