You can make 24 4-digit numbers. 1111 2222 3333 4444 5555 6666 1234 2345 3456 1356 6543 5432 4321 1432 ok i give up!
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.
There are 256. Some of them are: 1111, 1112, 1113, 1114, 1121, ... 2111, 2112, 2113, ... 3111, 3112, ... 4111, etc.
The smallest is 1111 if repeats are allowed. If not, it is 1235.
(7777-6666)/1111 = 1 (4444+5555)/(9999/3333) = 3 8888/2222 = 4 4*3 + 1 =13
The binary number 1111 is 15. The digits in a binary number are exponents of 2 rather than 10, so that for a four digit number in binary, the digit places represent 8, 4, 2, 1 instead of increasing values of 10. 1111 = 8+4+2+1 = 15
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.
10
starting at 1111 and going to 9999, there are 9*9*9*9 combinations (1...9 for each digit) = 6561
1111
There are 256. Some of them are: 1111, 1112, 1113, 1114, 1121, ... 2111, 2112, 2113, ... 3111, 3112, ... 4111, etc.
24 = 16 1111 1112, 1121, 1211, 2111 1122,1212,2112,2121,1221,2211 1222,2122,2212,2221 2222
With each digit having only 2 possibilities, the answer is 2 to the 4th power, which is 16. The 4 is because there are 4 digits. Think about the binary numbers 0000 to 1111, there are 2 possibilities for each digit. If your constraint is that the digits must have at least one 2 and at least one 5, then eliminate the two combinations 2222 and 5555, and that answer would be 14.
9915 1159 5555 9999 1111
1111
1111, unless you allow negative number. In that case, the answer is -9999.
1111
The smallest is 1111 if repeats are allowed. If not, it is 1235.