Carlos Slim Helu vs. Steve Ballmer

Every Sunday, Slim's father would give him a 5-peso allowance and required him to record his purchases in a ledger. Before going into business, Slim taught algebra at UNAM, a university in Mexico City.

Ballmer and Microsoft cofounder Bill Gates were classmates at Harvard. Ballmer created a website called USAFacts.org for people to look up and understand where the government is spending money.