Doesn’t take an expert actually.
The base figure for the population includes all intentionally retired people, a massive population. The labor participation rate is never more than 70% or so. By design. Now it’s abysmal now - and it means the real unemployment figure is something like 12-15% - but not 42.
Sounds like CNN is sort of quoting Trump remembering something about payrolls as a percentage of the total civilian non-institutional population--
--which shows a % about where Trump's quoted by the always truthful CNN. In other words, things are as bad now as they were when Reagan was president. imho the number says more about today's economy than the headline unemployment, but we'll need to lose the "real-unemployment" name and perhaps call it the "not-employment rate".