Self-made billionaire Carlos Slim Helú, 71, developed his business acumen at a young age and attributes his success to one person: his father.
Now one of the world's richest men and Mexico's richest person due to his holdings in numerous Mexican companies, the business magnate boasts an estimated net worth of $70.2 billion, according to Forbes.
Growing up, his father Julián Slim Haddad owned a dry goods store and invested in real estate in downtown Mexico City.
Every Sunday, Haddad would give his son an allowance of five pesos and make him write down all of his childhood purchases in a savings book, Forbes reports. Together, they would review the ledger and analyze his expenses, purchases and activities.
This helped Slim learn how to manage his income and expenses early on. In fact, Slim still keeps some of his childhood savings books on a shelf in his office, according to Fortune.
In a New Yorker article, Slim recalls some of his father's lessons, which include: "Money that leaves the business evaporates" and "All times are good if you work in the right way."