According to most of the characters in the book, Zero is a big fat zero. Okay, maybe that's obvious, but it's also a key part of the story, so we'll take a look.
Everyone in Holes seems to be convinced that Zero is a real nothing of a kid. Mr. Pendanski, in particular, mocks and belittles Zero at every turn. Even after the little guy runs away and is assumed dead, Mr. Pendanski won't give him a break: "He had nobody… He was nobody" (31.36). He may be right about the first part, but it doesn't make it any nicer.
Zero is physically small and definitely lacking in the toughness and aggression that most of the other boys seem to possess. For this reason, the kids his own age don't really consider him much at all: he kind of just falls by the wayside. X-Ray doesn't even bother to give him a nickname (his last name is Zeroni), maybe because the name "Zero" seems so fitting.
Even our hero Stanley doesn't appreciate Zero at first. As he settles into life at Camp Green Lake and begins to understand how things work in this new environment, Stanley reflects that, "He didn't care what Zero thought. Zero was nobody" (18.7).
Through the things he says (and more often, doesn't say) Zero reinforces this image of himself as someone who just doesn't matter. When spoken to or asked a direct question, Zero's typical response is, well, no response at all. In fact, the sentence "Zero said nothing" shows up more than ten times in the book. (Don't believe us? We dare you to count.)
Used to making it on his own on the streets, without even a mother to watch over him, Zero has learned to take advantage of his own invisibility, and to use his status as a nobody to help him survive.
Zero's name, of course, says a lot about him and about his place in the world. When Stanley teaches him to write his name, he thinks about what having a name like Zero means. And when Stanley thinks, he thinks deep:
Stanley watched him write it over and over again.
Zero Zero Zero Zero Zero Zero Zero…
In a way, it made him sad. He couldn't help but think that a hundred times zero was still nothing. (27.31-33)
This passage makes explicit what everyone in the book assumes about Zero. His silence, his lack of a family, his apparent absence of any significant claim on anyone – it all adds up to Zero's absolute powerlessness. And as a result, Zero is disregarded and disrespected by everyone around him. Overall, not a great way to live.
But here's the thing: Zero is a lot like the all the holes in the book – he's a blank space that seems like nothing, but actually contains a great treasure. Zero ultimately proves to be much tougher and smarter, and far braver than any of the other boys. And of course, as Madame Zeroni's great-grandson, his friendship with Stanley is the key to breaking the curse. Zero is the guy who convinces Stanley to break out of his shell and start his life over.
You could even say that Zero is really the center, the crux of the whole book. Without Zero, you wouldn't have anything at all. Now how's that for some new math?