20-(     )=3

19-(     )=0

(     )-8=11

11-(     )=10

16-(     )=12

16-(     )=15

(     )-4=8

(     )-4=15

17-(     )=12

(     )-7=7

15-(     )=10

20-(     )=1

13-(     )=4

(     )-6=6

(     )-2=11

14-(     )=4

(     )-5=11

(     )-2=15

14-(     )=2

(     )-5=9

(     )-4=11

(     )-14=6

16-(     )=16

12-(     )=4

13-(     )=8

16-(     )=13

(     )-3=10

(     )-4=8

(     )-7=11

(     )-8=10

(     )-16=1

(     )-7=10

(     )-1=11

13-(     )=2

(     )-1=11

(     )-7=8

(     )-15=3

(     )-14=5

(     )-6=7

(     )-5=9

11-(     )=0

15-(     )=3

(     )-16=3

19-(     )=8

(     )-20=0

(     )-8=8

14-(     )=14

20-(     )=19

(     )-1=12

(     )-15=4