(     )-7=12

4+(     )=13

13+(     )=16

16+(     )=18

9+(     )=12

13+(     )=19

17+(     )=18

(     )-1=13

11+(     )=15

(     )-12=8

9+(     )=20

20-(     )=15

(     )-2=13

15+(     )=19

(     )-1=10

14-(     )=1

16-(     )=16

(     )-6=8

(     )+14=20

(     )+11=19

18+(     )=19

(     )+2=20

(     )+2=14

(     )+9=20

1+(     )=12

10+(     )=18

(     )+19=20

20-(     )=5

(     )-1=15

(     )-18=0

14-(     )=2

3+(     )=16

(     )+19=19

(     )+1=15

18-(     )=13

(     )+2=19

16+(     )=16

13-(     )=5

13+(     )=16

13-(     )=9

11-(     )=2

12-(     )=1

13+(     )=20

12+(     )=17

18-(     )=4

(     )-8=4

9+(     )=16

(     )+3=19

12-(     )=8

11-(     )=3