For the uninitiated, the joke is:

spoiler

Each number should has a maximum value of 255.

The fact that I have a test in school today, and this is probable questiom in it, and this post reminded me of it,  thanks I guess? 

Each number between the dots is made up of 8 bits, so each one is a maximum of 255.

Update, they didn’t ask that questiom. For the exam XD