How many four digit numbers are made of odd number?
If you're asking for 4 digit numbers where all four digits are odd, then the lowest number possible is 1111, and the highest is 9999. You only have 5 digits to work with. The answer is: 54 - 53 = 625 - 125 = 500.Subtract the 5 cubed for the numbers less than 1111, which are not four digits.