US President Donald Trump on Thursday doubled down on his claim that prescription drug prices had been cut by more than 100 per cent, a mathematically impossible assertion, while defending what he described as a “different way” of calculating reductions.Speaking at an event announcing a deal with drugmaker Regeneron, Trump said his administration had reduced drug costs by “500, 600 per cent,” before adding that the figures could also be framed as “50 or 60 per cent” depending on the method of calculation. “People understand that better… there are two ways of calculating,” he said.However, mathematically, while prices can rise by more than 100 per cent, they cannot fall beyond 100 per cent without effectively dropping to zero or turning negative, implying companies would have to pay consumers to use their products.US Health Secretary Robert F. Kennedy Jr echoed Trump’s defence, arguing that steep prior increases in drug prices meant subsequent reductions could amount to cutting more than 100 per cent of those gains. He cited a hypothetical example of a drug rising from $100 to $600, though analysts point out that this represents a 500 per cent increase, not 600 per cent.Kennedy Jr, referring to an exchange with Senator Elizabeth Warren at a congressional hearing, said: “She was saying, ‘It’s mathematically impossible to have a drug drop by 600 per cent cost.’ And I said, ‘Well, if the drug was $100 and it raised the price to $600, that would be a 600 per cent rise. If it drops from 600 to 100, that’s a 600 per cent saving, isn’t it?’ And the President used that mathematical device to illustrate the magnitude of the theft that has been happening against our country and our people.“However, the comparison is flawed. A rise from $100 to $600 is a 500 per cent increase (a $500 gain on the original $100), and a drop back to $100 amounts to about an 83 per cent decrease, not 600 per cent, because in both cases the $500 change is measured against different base values: $100 for the increase and $600 for the decrease.The remarks come amid scrutiny from lawmakers, including Senator Elizabeth Warren, who said such claims would imply drugmakers should be paying consumers.Trump also made disputed assertions on other issues during the event. He said the ongoing conflict with Iran had effectively met his earlier prediction of lasting four to six weeks, despite the war continuing beyond that timeframe. Additionally, he revived his longstanding claim that attendance at his 2017 inauguration rivalled or exceeded that of Martin Luther King Jr.’s 1963 “I Have a Dream” speech — a comparison widely challenged by available crowd estimates.