Seitokai Sousenkyo

Kanon Miura is a freshman in high school who belongs to the student council. Everything is peaceful until ping-pong club president Kaede Tamaki intrudes on the student council, which somehow results in all of the members joining the ping-pong club… Follow the adventures of 5 cute girls from both the student council and ping-pong club in this slice-of-life four-panel manga!

(Source: Manga Box)