FPS refers to how many images, known as frames, are shown during one second. A good game displays between 30 to 60 FPS.

Let's divide a second by 30 to see how long a frame lasts on screen when we play at 30 FPS.

Wow, that's not a lot of time at all!

Because we have 30 frames that need to appear during one second, we need to divide that second to 30, meaning 1/30.