To piggyback on stetim94s answer:
I’m new to this, too. But the 10 % 10 basically looks how often you can fit ten into ten and then returns THE REST that wasn’t covered by this process.
Since 10 “fits” into 10 one time and leaves no rest, the return is 0, which is the same as 20-10*2, so it is not < as, but =. And since the operator looks for smaller OR equal (the latter being true), the statement is true.
I hope this makes sense, I also don’t understand everything yet and to makethings worse, I’m not a native speaker, so excuse me, if the description is a bit… clunky.