There are 10*10*10*10 = 10,000 possible combinations! You can get 1,048,576 possible combinations with a 4 digit lock.
There are 10,000 possible combinations that the digits 0-9 can be arranged into to form a four-digit code.
For each choice of the first two digits you have 10 choices for the third digit. Thus you have 10x10x10 = 1000 choices for the first three digits. Finally you have 10 choices for the fourth digit and thus there are 10x10x10x10 = 10 000 possible 4 digit combinations from 0-9.
There are 10,000 possible combinations that the digits 0-9 can be arranged to form a 4-digit pin code. Out of these ten thousand codes, which is the least commonly used? Which of these pin codes is the least predictable?
It's very simple. In 4 decimal digits there are 10,000 (0000 to 9999) possible values. The odds of any one of them coming up randomly is one in 10,000. A specific "4 digit number" would have 1/9000 chance, since there are 9000 4 digit numbers (1000-9999).
A common PIN is a guessable PIN
The DataGenetics group found that the three most popular combinations—1234, 1111, and 0000—account for close to 20 percent of all four-digit passwords. Every four-digit combination that starts with 19 ranks above the 80th percentile in popularity.
By the way, the most common four-digit PINs according to the study are: 1234, 0000, 2580, 1111 and 5555 (scroll down for a longer list) – 2580 is there because it is a vertical column on a numeric keypad.
The total number of permutations is 6 x 4 = 24. There are 24 ways to arrange the 4 items on a bookshelf. You probably don't want to draw tree diagrams for every permutation problem.
How many different combinations can you make with the numbers 1234? So there are {1,2,3,4} these 4 numbers. So there are 64 total ways.
(Although, as Data Genetics acknowledges, you probably shouldn't go out and choose “8068” now that this is public information.) Rounding out the bottom five are “8093,” “9629,” “6835,” and “7637,” which all nearly as rare.
There are 9000 four digit numbers in all.
For instance, the first digit of the 4-digit number must be either 1 or higher than one and the other three digits may be any digit that can start from 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Moreover, you know very well all the Four-digit numbers begin after 999.
How many 4 digit combinations with no repeats? Hence total number of permutations = 9×504=4536.
Multiplying 4 X 3 X 2 X 1 results in a product of 24. Therefore, the answer is you can make 24 4-digit numbers with 1234.
Combinations are a way to calculate the total outcomes of an event where order of the outcomes does not matter. To calculate combinations, we will use the formula nCr = n! / r! * (n - r)!, where n represents the total number of items, and r represents the number of items being chosen at a time.
So the required largest 4-digit number is 9965.