WATCH: Trump Tanks Chicago Economic Forum Interview Amid Calls For Him to Drop Out

Donald Trump followed up his bizarre performance in Oaks, Pennsylvania, on Monday night--which once again saw calls for him to drop out of the race-- with a combative interview at the Chicago Economic Forum hosted by the editor-in-chief of Bloomberg News, John Micklethwait.

Trump once again lied about January 6th and showed his full lack of understanding as to how tariffs work, insisting that his proposed tariffs wouldn't have negative consequences in a possible second term.

Micklethwait repeatedly pressed Trump over his plans to impose a universal tariff on imports and his threats to use tariffs on American companies that outsource their manufacturing, noting that Trump’s plans would "essentially halt trade with China, place at least a 10 percent tariff on European nations and have a drastic effect on the U.S. economy, where 40 million jobs rely on trade."

“It’s going to have a massive effect — positive effect. It’s going to be a positive effect,” Trump responded. “It must be hard for you to spend 25 years talking about tariffs as being negative and then have somebody explain to you that you’re totally wrong.”

Trump is the totally wrong one, as Micklethwait went on to prove by telling Trump that critics have said his tariff proposals for all imports would amount to a national sales tax, with $3 trillion worth of imports affected and companies passing on higher costs to buyers.

“That is just simple mathematics," he told Trump, who didn't like that.

“It is, but not the way you figured. I was always very good at mathematics,” Trump replied, trying to cover up the fact that he doesn't understand tariffs.