Hi Utku,
If there are only a few options, one approach is to load parserOneOf.pl. Then you can define the answer to be OneOf(0,2,4,6,8);
http://webwork.maa.org/pod/pg_TRUNK/macros/parserOneOf.pl.html
You can write a custom answer checker that literally checks if the submitted answer is even, greater than or equal to 0, and less than or equal to 8:
http://webwork.maa.org/wiki/Custom_Answer_Checkers
With that approach, you have to declare one number to be "the correct answer" as far as what gets displayed to a student as the correct answer after the answer date.
Alex
WeBWorK Main Forum
Setting the answer as one of a few answers
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