Infinity. Numbers never end!
42 of them.
450
29 of them.
There are 898 three-digit even numbers. Nine of them are multiples of 55. That leaves 889 * * * * * There are 450 three-digit even numbers and 17 of them are multiples of 55. So that leaves 433.
Three numbers.
There are 450 of them.
There are 720 of them.
There are 22 such numbers.
There are 9*10*9 = 810 such numbers.
Only the multiples of 1000.
The 3-digit counting numbers are 100 through 999 = 900 numbers.Half them are multiples of 2 (even numbers).The other half are not . . . 450 of them.