While Donald Trump takes heat for his policies on the presidential campaign trail, Mother Jones just unearthed some evidence that his math skills aren't quite up to snuff either.

Watch Trump incorrectly multiply 17 x 6, arriving at 112 as the answer. The correct answer is 102. Then watch him gloat that he got 112 under the misguided notion that he outsmarted his children, Ivanka and Donald Jr.

This math-block moment hails from a 2006 visit to Howard Stern's radio show, MJ reports. Trump's kids bragged in the clip that their dad couldn't buy their way into Wharton and that they had to earn entry on their own merits.

It's then that Stern launches the pop quiz. In all fairness, doing even relatively easy multiplication might be tough with an audience. But you'd think at some point that one of the Trumps might come up with the right answer.

President Barack Obama told Jay Leno on "The Tonight Show" in 2012 that he was no math wiz either, but we doubt he'd get stumped on 17 x 6.

Editor’s note: Donald Trump regularly incites political violence and is a serial liar,rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims — 1.6 billion members of an entire religion — from entering the U.S.