Why is Zero good at Math?

[Sandy]

He is the descendant of Madame Zeroni, an Egyptian fortune teller, so Zero takes after Madame Zeroni and good at calculation. :)

Besides a very wide mouth:
"When she (Madame Zeroni) looked at you, her eyes seemed to expand, and you felt like she was looking right through you."

"If anybody had X-ray vision, it was Zero."

[Jasmine]

I thought it was because he was suppose to be autistic. We can not be sure of this as the book never confirms it but he does show a lot of characteristics.

[Danielle]

idk... the movie/book never really said anything

[Yomna]

May be because he stays without talking a lot of times , so he have some experience .. and this can make him more intelligent

[Dante]

I really don't believe there's any deep meaning behind it.

Some people just have a natural affinity for maths...