Cirno decided to do his perfect math class ! Become a genius like her ! When Cirno teaches, answer by the wrong answer. Except when it is 9 who is always a good answer! Sometimes Daiyousei replaces Cirno, so just answer the math. Rumia, Mystia and Wriggle also participate in the class, but are not very disciplined ! Cirno-sensei is a fangame of Touhou Project, Team Shanghai Alice and Cirno's Perfect Math Class, Tetla Pot x IOSYS.