13-(     )-2=6

(     )-4-1=9

11-6-(     )=0

18-12-(     )=5

10+(     )+2=20

(     )+7+0=19

17+(     )+0=20

15+(     )+1=18

18+2+(     )=20

15-(     )-1=11

(     )-5-4=8

14+(     )+2=16

(     )+2+3=19

18+(     )+1=20

(     )+5+0=19

(     )+1+10=17

(     )+14+0=15

15-8-(     )=0

9+(     )+1=20

17+(     )+2=20

(     )-3-7=2

1+(     )+2=20

11+(     )+3=19

18-(     )-13=5

(     )-14-1=1

16-1-(     )=6

11-10-(     )=0

16-14-(     )=0

18-11-(     )=1

16-3-(     )=1

16-12-(     )=0

17+(     )+0=20

(     )+9+0=19

12-(     )-2=4

14+2+(     )=19

18-10-(     )=1

(     )-2-6=3

(     )+8+2=19

18+(     )+1=20

(     )+1+1=17

13+(     )+1=20

(     )+7+0=20

(     )-2-2=8

1+(     )+3=15

(     )-7-2=3

(     )-3-5=12

(     )-2-5=4

4+5+(     )=20

(     )-14-0=3

10+(     )+3=20