Bill Gates is the richest man in the world. Unlike Donald Trump, there has been independent verification of his net worth, which is currently estimated to be about $76 billion. Also unlike Trump, Gates made his money by selling actual products to people and not on the sort of smoke-and-mirrors flim flam that is currently being exposed at Trump University.At a recent event, the topic of Trump s claim that he donated to veteran s charities came up, and Gates   who heads one of the largest charities in the world   made a dig at the presumptive Republican presidential nominee.Gates took the jab at Trump during an interview alongside his wife, Melinda, at a panel discussion hosted by the news outlet ReCode. He hasn t been known for his philanthropy. He s been known for other things,  Gates said to laughter, when asked if the presumptive GOP presidential nominee had been approached to sign a pledge to give away at least half of his wealth to philanthropic causes.Trump was shown to only cut checks to veteran groups after the Washington Post asked him to back up his boasting about donating $6 million months ago on the same day he boycotted a Fox News debate, arguing that moderator Megyn Kelly had been mean to him.By comparison the Bill and Melinda Gates Foundation already has $44 billion at its disposal, thanks to the couple parting with some of the money generated from Microsoft. It has made major investments around the world in education, health, and more.Gates and his wife Melinda are also part of a group of the super-rich who have signed  The Giving Pledge  in which they promise to give more than half of their wealth to charity during their lifetimes, or in their wills. Several real life billionaires have signed the pledge, including Warren Buffett, Mark Zuckerberg, Larry Ellison and others. But they haven t approached Trump yet.Melinda Gates, with a smirk, said the couple has not approached Trump, adding that they are still working their way down Fortune s list of billionaires. We don t have any immediate plans to approach him,  she said.  I think we should probably let this cycle play itself out before we do anything related to that. Gates may just be being polite. Previous reporting has indicated that Trump may not even be worth $1 billion, far less than the $10 billion he has been claiming. He has refused to release his tax returns, which some believe proves he is hiding that he is a millionaire and not a billionare.Featured image via Flickr