13+(     )-4=15

6-(     )+10=15

15-(     )+0=2

(     )-13+4=11

7+12-(     )=8

15+(     )-2=17

17+(     )-1=17

18+(     )-1=18

20-(     )+7=13

13+(     )-1=17

4+15-(     )=7

(     )+2-2=9

13+(     )-6=14

(     )-1+12=13

6-(     )+13=16

6+6-(     )=8

4-0+(     )=19

(     )-8+11=12

7-1+(     )=12

(     )-1+14=14

11+6-(     )=16

16-10+(     )=9

5-3+(     )=14

17-16+(     )=8

9+4-(     )=10

(     )-1+6=16

2+9-(     )=2

15-(     )+1=1

11-(     )+4=5

0+(     )-17=0

2-(     )+13=14

(     )+2-0=18

(     )-10+1=3

11-5+(     )=19

13+(     )-3=14

4+15-(     )=14

15-(     )+8=10

17+(     )-0=17

20-3+(     )=17

11-7+(     )=5

20+(     )-0=20

10-(     )+11=14

4-(     )+16=17

2-(     )+11=11

14-1+(     )=14

(     )-6+9=11

18-(     )+15=17

20-18+(     )=17

3+(     )-9=11

11+(     )-0=18