Hi @mmatuszewski 

The option for partial credit in Multiple Answer questions is "partial credit with penalty"

You can choose to award partial credit with penalty or require an exact match for Multiple Answer questions. The partial credit with penalty option awards points for each correct answer selected and deducts points for each incorrect answer selected. Exact match awards full credit only if all correct answers are selected and no incorrect answers are selected.

(per https://community.canvaslms.com/t5/Instructor-Guide/How-do-I-create-a-Multiple-Answer-question-in-Ne... ).

So, in your screenshot, the student got partial credit for choosing "-2", but was penalized for also picking the incorrect answer "-1".  That prevents students from getting full credit for just selecting every answer.

There isn't a "partial credit without penalty" option.