7+(     )=13

(     )-15=1

19+(     )=20

16-(     )=12

(     )+6=15

7+(     )=16

12-(     )=1

17-(     )=2

(     )-11=2

18-(     )=13

(     )-13=0

(     )-0=19

11-(     )=4

(     )+5=18

14-(     )=4

(     )+4=17

(     )+1=20

(     )+0=12

(     )+1=20

(     )+2=16

(     )-8=3

15-(     )=10

18-(     )=7

(     )-2=15

6+(     )=18

17-(     )=11

(     )-15=0

(     )+14=18

19-(     )=19

2+(     )=18

(     )+15=20

(     )+1=16

(     )-1=13

(     )-4=14

(     )-12=4

20-(     )=17

16+(     )=16

4+(     )=15

13-(     )=0

15-(     )=12

(     )+12=20

3+(     )=11

(     )+3=18

4+(     )=15

(     )-14=2

13-(     )=6

(     )+3=14

(     )-6=6

(     )+14=17

(     )-13=7