“Fake math” returned to the Oval Office on Thursday as President Donald Trump defended his past claims about prescription drug price reductions during an event announcing a deal with drugmaker Regeneron. Speaking alongside his health chief, Robert F. Kennedy Jr., Trump acknowledged he had boasted that his efforts to reduce drug prices cut what consumers pay by “500%, 600%.” He added that he and his aides also used another set of numbers, saying, “We also sometimes say 50%, 60%,” and argued that the figures could go higher—“70, 80 and 90%”—depending on how the change is calculated.

Trump said people “understand that better,” and he told reporters “they’re two ways of calculating” and that “either way, it doesn’t make any difference.” Kennedy had raised the issue earlier during the same Oval Office event, describing how he views the percentage changes as they relate to both prior price increases and subsequent cuts. Kennedy said he was reminded of his own exchange with Sen. Elizabeth Warren, D-Mass., the previous day at a congressional hearing, when Warren criticized claims that would imply drug makers should effectively pay consumers to take their drugs.

At that congressional hearing, Kennedy described Warren saying that asserting price cuts exceeding 100% might suggest “companies should be paying you to take their drugs.” Kennedy then argued that manufacturers had raised prices on popular medications by more than 100% and that Trump’s approach to “cutting the price down substantially” effectively “wip[es] out” percentages of costs that Kennedy said were worth more than 100%. Kennedy also used a numeric example: “If the drug was $100, and it raised the price to $600, that would be a 600% rise,” he said, while noting the increase from $100 to $600 is actually only 500% in the way he said the calculation should be done. Kennedy continued: “And the president used that mathematical device,” even as the Associated Press reported that no equivalent “device” exists to justify the way Trump characterized the percentage reductions.

Trump’s remarks on Thursday followed what the AP described as a repeated pattern of using percentages in a way the report said does not align with standard mathematical treatment. The AP described how price changes framed as reductions by more than 100% would require a starting-point framework that effectively drives the price to zero and then beyond into negative territory, where consumers would need to be paid for the product. During the event, Trump defended the approach anyway, telling reporters that the difference between the methods “doesn’t make any difference.”

In the same Oval Office appearance and question-and-answer session, Trump also returned to other figures that had drawn attention, including the length of the Iran conflict. The AP reported that Trump defended a claim that the 7 1/2-week-and-still-going Iran war fell within the four- to six-week timeline he had predicted earlier, arguing that Iran’s military was “decimated” by then. The report noted that the United States and Iran agreed to a ceasefire earlier this month, and that Trump announced this week that he was extending it, but it said neither side says the war is over.

The AP said the event also included Trump’s remarks about the crowds at his 2017 inauguration, which had previously led to Kellyanne Conway popularizing the phrase “alternative facts.” On Thursday, Trump again pointed to photos and said he had “the same exact crowd,” adding that he believed he had “more people,” and then said, “But that’s OK.”