17+(     )=17

(     )-1=10

9+(     )=14

13+(     )=18

(     )+8=12

18+(     )=18

(     )+2=16

(     )-1=16

13-(     )=4

(     )+10=18

6+(     )=13

(     )+1=19

(     )+12=17

17+(     )=19

4+(     )=20

(     )+1=20

20-(     )=12

1+(     )=16

(     )+10=15

11+(     )=13

(     )-9=2

(     )-10=4

3+(     )=11

14-(     )=9

17+(     )=20

(     )-10=6

1+(     )=15

12+(     )=13

(     )+10=16

(     )-3=13

(     )+5=18

(     )+10=15

(     )-1=12

6+(     )=18

17-(     )=14

16-(     )=11

3+(     )=17

4+(     )=12

(     )-3=13

17-(     )=5

(     )-15=1

(     )-15=4

15-(     )=0

10+(     )=18

(     )-15=1

(     )-16=1

12-(     )=6

13-(     )=3

(     )+14=17

(     )-10=2