Self-made billionaire Carlos Slim Helú, 71, developed his business acumen at a young age and attributes his success to one person: his father.
Slim, who reigned as the world's richest person from 2010-2013, learned about the world of business at age ten, according to his biography.
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."
By following his father's financial advice, Slim quickly began to build his own wealth.
At 10, he opened his first checking account. He soon withdrew his money and began buying government savings bonds for ten pesos because he was not receiving a big enough return on his deposit, according to the New Yorker.
At 12, he began buying shares of Banco Nacional de México. Three years later, he became a shareholder at the bank, according to the book "Managing New Ventures: Concepts and Cases in Entrepreneurship."
Slim continued investing throughout high school and attended his first board meeting for a mining company that he wanted to invest in as a teenager, NBC News reports.
Upon graduating from college with a degree in civil engineering, the business tycoon started to buy stock in companies and build his fortune. But it wasn't until Mexico's economy plunged in 1982 that he amassed most of his wealth.
With the country suffering its worst recession since the Great Depression, Slim went on a buying spree and invested in Mexican companies at record-low prices.
"I learned from my father that you continue to invest and reinvest in your businesses, including during crises," Slim explains in the book "No Fear of Failure."
Like this story? Like CNBC Make It on Facebook
See also:
3 TED Talks you should watch if you want to be successful
The Ivy League grad who just became Miss America says this mentality led to her success
