Which excerpt from the number devil best shows that one purpose of robert's character is to oppose the number devil?

“you sound as though you never went to school. or maybe you are a teacher yourself? ”
"how dumb can you get! " said robert. "a colossal waste of time if you ask me. so get going! scram! shoo! "
"i'm sorry," robert said meekly, though the whole thing was getting weirder and weirder.
"it's just that all those ones give me a headache. they actually make things more complicated than they are."