President Biden appeared to invent a vast new number as he tried to boast about his administration’s massive infrastructure spending — a brain-twisting bungle that the White House sought to downplay in its official transcript.

“On my watch, instead of Infrastructure Week, America is having Infrastructure Decade,” the president told a crowd of union members in Las Vegas on Friday, in a speech touting federally funded railroad projects.

“Over a billion three hundred million trillion three hundred million dollars!” Biden exclaimed. “Trump just talks the talk, we walk the walk.”

The jab was meant as a swipe at Biden’s predecessor, former president Donald Trump, who did not pass such spending bills through Congress during his tenure — but it drew mockery online.

“Why does the President of the United States sound exactly like my 4-year-old when he’s trying to come up with the highest possible number?” wondered Biden critic Oren Ross on X.

On Saturday, nearly 18 hours later, the White House press office released a transcript that papered over the error by expressing it numerically, as “over 1,300,000,000 — $1,000,300,000,000” — hinting that the president had merely missed a few zeroes on his teleprompter, rather than dabbling in some new form of budgetary math.

The verbal stumble was the latest in a long string of Biden gaffes that have contributed to widespread voter worries about the 81-year-old president’s mental acuity and fitness for office.

In the same speech, Biden shared for at least the 13th time since taking office a debunked story involving a late Amtrak conductor who supposedly exclaimed “Joey, baby!” while extolling Biden’s lifetime rail ridership.