Incidentally, that might not be the worst idea. Today Biden labelled Trump the United States' first "racist" president, seemingly forgetting that at least a dozen former presidents literally owned slaves.
I digress. The interviewer, veteran political journalist Chris Wallace, suggested to Trump that he had rather overhyped the test's difficulty.
"Incidentally, I took the test too, when I heard that you passed it," Wallace said.
"Yeah, how did you do?" the President asked.
"It's not the hardest test. It has a picture and it asks, 'What's that?' And it's an elephant," Wallace replied, a little dryly.
"See, that's all misrepresentation. It's all misrepresentation," Trump shot back.
"Because, yes, the first few questions are easy, but I bet you couldn't even answer the last five questions. I'll bet you couldn't. They get very hard, the last five questions."
"Well one of them was, 'Count backwards from 100 by seven'," Wallace said.
"Let me tell you. You couldn't answer, you couldn't answer many of the questions. I guarantee you Joe Biden could not answer those questions. And I answered all 35 of those questions correctly," Trump insisted.
Here's the thing. Versions of the Montreal Cognitive Assessment are publicly available, and none of the questions on it look particularly difficult. We have gone through them one-by-one here, if you're curious.
So, everyone who watched the interview was left to wonder which questions, exactly, Trump thought were "very hard".
Good news! We need wonder no longer. Today Trump gave another interview to Fox News, and he described in copious detail the part of the test that was supposedly so tough.
"It was 30 or 35 questions. The first questions are very easy. The last questions are much more difficult," he told the interviewer, Dr Marc Siegel.
"Like a memory question. It's like, you'll go, 'Person, woman, man, camera, TV.' So they say, 'Could you repeat that?' I said, 'Yeah. Person, woman, man, camera, TV.' 'OK, that's very good.'
"If you get it in order, you get extra points. OK now he's asking you other questions. Other questions. And then, 10 minutes, 15-25 minutes later, they say, 'Remember the first question? Not the first, but the tenth question? Give us that again. Can you do that again?'
"And you go, 'Person, woman, man, camera, TV.' If you get it in order, you get extra points. They said nobody gets in order. It's actually not that easy, but for me it was easy. That's not an easy question.
"In other words, they ask it to you, they give you five names, and you have to repeat them, and that's okay. If you repeat them out of order, it's okay, but you know, it's not as good.
"But then when you go back 20, 25 minutes later and they say go back to that question – they don't tell you this – go back to that question and repeat them. 'Can you do it?'
"And you go, 'Person, woman, man, camera, TV.' They say it's amazing. 'How did you do that?' I do it because I have, like, a good memory. Because I'm cognitively there."
There you have it. When Trump talks about the questions getting "very hard", he means the part when you have to remember a sequence five words.
The man who created the assessment in the 1990s, Dr Ziad Nasreddine, has stressed that it is not supposed to be a measure of intelligence.
"This is not an IQ test or the level of how a person is extremely skilled or not," Nasreddine, told MarketWatch this week.
"The purpose is to detect impairment. It's not meant to determine if someone has extremely high levels of abilities.
"It is supposed to be easy for someone who has no cognitive impairment."
But Nasreddine also called out critics of Trump for going overboard in "ridiculing" the test and making it sound "too simple", as though it were "a kindergarten test for five-year-olds".
"I think there's misinformation on both sides of the political divide," he said.
Again, if you're curious, you can see all the test's questions here.
