What 'Shark Tank' investor Kevin O’Leary teaches his kids about money

Michael Desmond | ABC

Kevin O'Leary may have 14-hour shoots and negotiations to tend to, but he is also a father.

At the top of his agenda at home is teaching his children the time and hard work it takes to make money. He's taught his children as early as the age of five that money is earned, not given. It's an aspect of parenting he's passionate about, and one about which he's written three books.

Teaching kids about money can start at the dinner table, where O'Leary talks about money as a family member. That may sound a bit outlandish, but it is a technique he swears by. After all, money plays a very real role: it helps manage the family and obtains necessities like food.

My kids understand what debt is and how risky it is.
Kevin O'Leary
'Shark Tank' investor

The key takeaway he wants his children to absorb?

"Money is something you don't just get on trees," he says. "Kids have to understand you earn it."

One of the simplest ways that O'Leary does this is by bringing his children along for errands. When he checks out, he uses cash. Unlike a credit card, which doesn't change when it's used, a stack of dollar bills noticeably diminishes once you pay for a product. At a young age, that's simple to see and understand.

The celebrity entrepreneur has found that the best age to teach children the "building blocks" skills of the money and savings has been before age 10.

"Today, my kids understand what debt is and how risky it is," he says. "They understand how to live within their means."

O'Leary's financial lessons aren't just talk, either. He puts them into practice, as when he flies first class but has his son fly economy, and he expects his children to put them into practice, too. They won't have a choice, since they won't be able to depend on his wealth: the investor has proclaimed that he won't be leaving his children an inheritance.

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Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank."