What was Helen's least favorite subject?

Helen's least favorite subject was math.

Arithmetic seems to have been the only study I did not like. From the first I was not interested in the science of numbers. Miss Sullivan tried to teach me to count by stringing beads in groups, and by arranging kindergarten straws I learned to add and subtract. I never had patience to arrange more than five or six groups at a time. When I had accomplished this my conscience was at rest for the day, and I went out quickly to find my playmates.