What happened to Auggie at school at least four to five times a day?

From the text:

In the hallways, which were always crowded, my face would always surprise some unsuspecting kid who maybe hadn't heard about me. The kid would make the sound you make when you hold your breath before going underwater, a little "uh!" sound. This happened maybe four or five times a day for the first few weeks: on the stairs, in front of the lockers, in the library.