There are 900 3-digit numbers, 100 to 999.
The 3 may be in the hundreds place, the tens place, or the ones.
The numbers 300 - 399 have 3 in the hundreds place.
The numbers 130, 131 ... 938, 939 have 3 in the tens place.
The numbers 103, 113, 123 ... 993 have 3 in the ones place.
That would total 100 + 90 + 90 = 280 except that now we have double counted some numbers with 2 or more threes in them. I believe if you count carefully you will find 19 double counted numbers in the 300 - 399 group and 8 numbers with the tens digit and ones digit equal to 3. Lastly, the number 333 was triple counted. 280 - 28 = 252. There are several ways to solve this problem. I encourage you to double-check my results ... who is to say this is correct?
There are 17 such numbers.
252
252
There are 5 numbers which can make the 3 digit numbers in this example. Therefore each digit in the 3 digit number has 5 choices of which number can be placed there. Therefore number of 3 digit numbers = 5 x 5 x 5 = 125
A credit card number is a 16 digit number.
To find the total number of seven-digit numbers that contain the number seven at least once, we can use the principle of complementary counting. There are a total of 9,999,999 seven-digit numbers in total. To find the number of seven-digit numbers that do not contain the number seven, we can count the number of choices for each digit (excluding seven), which is 9 choices for each digit. Therefore, there are 9^7 seven-digit numbers that do not contain the number seven. Subtracting this from the total number of seven-digit numbers gives us the number of seven-digit numbers that contain the number seven at least once.
There are 17 such numbers.
252
theres only 1 number which is 123456, the least digit is 1 and the greatest is 6
The answer will depend on how many digits there are in each of the 30 numbers. If the 30 numbers are all 6-digit numbers then the answer is NONE! If the 30 numbers are the first 30 counting numbers then there are 126 combinations of five 1-digit numbers, 1764 combinations of three 1-digit numbers and one 2-digit number, and 1710 combinations of one 1-digit number and two 2-digit numbers. That makes a total of 3600 5-digit combinations.
Routing number is 9 digit number.
There are 9000 4 digit numbers Find 4 digit numbers that are all different from 1 find 4 digit numbers that are all different from 1 The thousands digit has 8 ways to choose, hundreds, tens, and units all have 9 ways => there are 8 x 9 x 9 x 9 = 5832 digits => 4 digit numbers contain at least 1 digit 1 = number of 4 digit numbers , the number of 4 digit numbers is different by digit 1 =9000 - 5832 = 3168 numbers
There is only one number and that is 123456.
Number of 7 digit combinations out of the 10 one-digit numbers = 120.
252
300
There are 5 numbers which can make the 3 digit numbers in this example. Therefore each digit in the 3 digit number has 5 choices of which number can be placed there. Therefore number of 3 digit numbers = 5 x 5 x 5 = 125