共30题用时5分钟

13-8=

18-9=

12-8=

10-3=

16-7=

14-7=

11-2=

10-1=

15-6=

11-8=

10-3=

11-9=

12-7=

13-9=

16-7=

16-9=

15-6=

15-9=

16-9=

11-9=

13-7=

13-8=

16-8=

16-9=

14-9=

18-9=

17-8=

13-6=

10-1=

13-9=