1) The US workforce is 164.6 million people.
1) Before the crisis, 96.5% of Americans who wanted to work were working. So, 5.76 million were not working.
2) At the last measurement, 88.9% of Americans who wanted to work were working. So, now, 18.2 million people are not working.
4) One assumes that the people who can't pay their rent/mortgage are the ones not working. (There will of course be some frothiness around the edges, with some who ARE working not being able to pay the rent due to fewer hours, offset by some who are not working but who have a partner who IS working, so they're not at risk.)
18.2 million is not 40 million. CNBC needs to ask their sources who provided this number some hard questions.