Hehehe, ok.

Those require lines there, they're importing code written elsewhere. We call that code a library. Take the first one:

var zero = require("number-zero");

defines a variable called zero, imports a library called number-zero (not a real library btw, just a joke), and assigns its value (assumed to be the constant 0) to the variable. Later in line 19, zero is read.

The joke is that you wouldn't even write line 2 and use a simple 0 instead of zero in line 19. The code is full of unnecessary imports of basic language components.