Of the 35 students in my class, 11 practice taekwondo, 11 play piano, and 20 take math lessons. 4 students play piano and go to math lessons, 3 students do taekwondo and play piano, 5 students go to math lessons and practice taekwondo, and 3 students do none of these. How many students do all 3?

Thank you to the people who will answer this!

Guest Jun 13, 2021