# How combination in a 9 digit number?

There are different numbers of combinations for groups of different sizes out of 9:

1 combination of 9 digits

9 combinations of 1 digit and of 8 digits

36 combinations of 2 digits and of 7 digits

84 combinations of 3 digits and of 6 digits

126 combinations of 4 digits and of 5 digits

255 combinations in all.

### Carlin wrote a 447 page book on the history of mathematics. She numbered the pages by hand beginning with page 1. How many total digits did she write when numbering the pages?

Answer 1 x 9 (number of 1 digit numbers) plus 2 x 89 (number of 2 digit numbers) plus 3(number of 3 digit numbers) x 347 = 1228 The correct answer is 1323. Here is how you do it. 1 digit numbers = 9 2 digit numbers = 90 (99-9) number of 2 digit numbers - number of 1 digit numbers 3 digit numbers = 378 (477-99) number of 3 digit numbers - number of…

### How many 3-digit numbers can be formed using 0123456789 when repetition is not allowed?

Assuming a 3-digit number does not start with a zero (ie a 3-digit number is one of 100-999): There are 9 possibilities for the first digit (1-9); for each of these there are 9 possible remaining numbers for the second digit; for each of these there are 8 possible remaining numbers for the last digit; giving 9 x 9 x 8 = 648 possible numbers.

### What are all 5 digit combinations with 1-9?

from 1-9 have 9 numbers so that we have 9*9*9*9*9=59049 Consider the case of 5-digit number combinations, where each is some digit from 1 through 9. There are 9 different digits you can pick for the first number. Assuming you can have repeats, there are 9 you can pick for the second, 9 you can pick for the third, and 9 you can pick for the fourth and 9 you can pick for the fifth.

### Are there more 11 digit or 12 digit palindromic numbers?

There are the same number: any twelve digit palindrome is just an eleven digit palindrome with its central digit repeated. In general, if we are considering numbers of n digits: For even values of n, the number of palindromes is 9 x 10n/2 - 1 For odd values of n, the number of palindromes is 9 x 10(n-1)/2

### What is the one 9 digit delectable number which can be made using the digits 1 to 9?

A delectable number has nine digits, using the numbers 1-9 once in each digit. The first digit of a delectable number must be divisible by one. The first and second digits must be divisible by two, the first through third must be divisible by three, etc. There has only been one delectable number discovered: 381654729.

### How many 5 digit palindromes are there?

900 This explains it. A positive integer is a palindrome if it reads the same forward and backwards such as 1287821 and 4554. Determine the number of 5-digit positive integers which are NOT palindromes. We start by counting the total number of 5 digit positive integers. The first digit is between 1 and 9, so we have 9 choices. Each of the other 4 digits can be anything at all (10 choices for each). This…

### How do you know if a number is divisible by 9?

The easiest way is to test it. Divide the number by 9, and see if the result is an even number, or if there is a fractional amount in the answer. This is quite easy to do with a calculator, but can be done by hand as well, if you know how to do long division. To test a number without doing the division: Add the digits of the number together and if this sum…

### You are a three digit number your tens digit is five more than your ones digit your hundreds digit is eight less than your tens digit What number are you?

194 Think of it as three separate numbers, A, B, and C (left to right). The first statement says B = C + 5 The second statement says A = B - 8 You know all three numbers have to be less than or equal to 9, and you know the first number has to be greater than or equal to 1 (otherwise you'd only have a two-digit number). So take the two statements, plus…

### What are the First 4 multiples of 9?

They are 9,18,27, and 36. A general rule for finding if a number is a multiple of 9: 1: Add the digits of the number. 2: Repeat step 1 until you get a single digit. 3a: If the digit is 9, your original number is a multiple of 9. 3b: If the digit is not 9, then your original number is not a multiple of 9. Examples: The number is: 223243628 Add the digits: 2+2+3+2+4+3+6+2+8=32…

### If you have 9 numbers how many different 6 digit combinations?

We treat this as a permutations and combinations problem... as there are two possible 'rules' involved. If we are allowed to repeat a digit (such as 456537 - which as two 5s in it) then there are 9 options for every digit. So 9 x 9 x 9 x 9 x 9 x 9 = 531441 different six-digit numbers from a choice of 9. If we cannot repeat a digit, as we did above, thee…

### What is an equivalent decimal for 9 thus?

A decimal number is simply a way of representing a number in such a way that the place value of each digit is ten times that of the digit to its right. If it does not contain a fractional part then the decimal representation does not require a decimal point. So the decimal for 9 thus is 9 thus (whatever thus might be).

### How do you solve the game where you Pick any two digit number then subtract the first digit then subtract the second digit and guess the answer?

Given a two digit number --> xy The numerical value of that number is 10x + y (The x is in the ten's place and the y is in the one's place.) So, if you subtract each digit from the original number, here is the resut: 10x + y - x - y = 9 x Based on that simple algebra, the answer will always be nine times the first digit. People often tend to…

### What Bank branch this Sort Code 72-50-00?

All Alliance & Leicester accounts have this sort code, no matter which branch they are registered to. The final digit, 0, is usually replaced by the first digit of the person's 9-digit account number, leaving them with a more common 8-digit account number. For instance, if my account number was 123456789, my sort code would be 72-50-01 and my account number 23456789.

### What three digit number divided with a single digit will result in a remainder of 8?

There will be more than one answer. To have a remainder of 8, the divisor must be greater than 8. The only single digit greater than 8 is 9, so 9 must be the divisor. Since 8 is 1 less than 9, the dividend needs to be one less than a multiple of 9. Candidates are values of 3 digits, as the problem states. The lowest 3-digit number satisfying the condition is 107 (which is…

### What is the greatest 2-digit composite number?

The greatest two-digit composite number would be 99, since 99 can be divided by 11, 9, and 3. I you look around this number, you will see why: 98 is also a composite number, but it is smaller than 99. 100 is also a composite number, but it has three digits. 97 has two digits, but it is a prime number. On the other hand, 99 divided by 11= 9, 99 divided by 9= 11…

### Is 796 divisible by 8 show the working?

Add 4 times the hundreds digit to twice the tens digit to the units digit. If this sum is divisible by 8, then the original number is divisible by 8. If this summing is repeated until a single digit remains, if this digit is 8, then the original number is divisible by 8 otherwise it gives the remainder of the original number divided by 8 (unless it is 9, in which case the remainder is…