Mathematics.

Karen's first class was math, something she was extremely glad about. It made her easier to fake being sick or something. She was her teacher's pet, which made things even better for her plan.

Entering the classroom, she greeted her teacher, before she walked to the back of the classroom, taking her seat near the window.

Eventually, midway during class, she raised her hand before asking for permission to head to the infirmary. Making a convincing attempt of a cough, the teacher gladly allowed her to go.

She bowed, thanked the teacher, before leaving the classroom, much to her joy.