Let's count them out...
12
20
21
22
23
24
25
26
27
28
29
32
42
52
62
72
82
92
Whew... that makes 18 two-digit numbers that have a "2".
172
04,14,24,34,40,41,42,43,44,45,46,47,48,49,54,64,74,84,94.... OR 19 Digits
There is only one such number.
17
There are 175 such numbers.
18.
172
04,14,24,34,40,41,42,43,44,45,46,47,48,49,54,64,74,84,94.... OR 19 Digits
17
There is only one such number.
There are 156 such numbers.
There are 195 such numbers.
There are 175 such numbers.
1
-2
There are 9000 4-digit numbers. 8*9*9*9 = 5832 of them do not contain a 5 The remaining 3168 contain a 5.
greatest two digit number is 99. smallest whole number is 0 there fore 99-0=99