Best Answer

If you don't mind beginning the 4-digit number with one or more zeros, then

there are 10 choices for each digit, and the total number of possibilities is:

(10 x 10 x 10 x 10) = 10,000 .

If the 4-digit number can't begin with a zero, then there are only 9 choices for

the first digit, but 10 choices for each of the others, and the total number of

possibilities is:

(9 x 10 x 10 x 10) = 9,000 .

Q: How many four digit numbers can be formed using the digits 0123456789 if the repetitions of digits are allowed?

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10,000

There are 10 numbers in all including 0. The first space can be filled in 9 ways (as we have to exclude 0). The second through sixth spaces can be filled in 10 ways as 0 can be included. Totally, 9 x 10 x 10 x 10 x 10 x 10 or 9 x 10^5 digits can be formed if repetition is allowed.

120 There are 6 digits in total. The numbers with 3 digits, with all digits distinct from each other, are the permutations of the 6 digits taken 3 at a time, and therefore there are 6*5*4 = 120 of them.

525

Assuming that the first digit can't be zero: If repetition of digits is permitted: (5 x 6 x 6) = 180 numbers of 3 digits. If repetition of digits is not permitted: (5 x 5 x 4) = 100 numbers of 3 digits.

Related questions

pizza

There are 5 numbers of 1 digit, 25 numbers of 2 digits, and 75 numbers of 3 digits. This makes 105 numbers in all.

The number of six digit numbers that you can make from ten different digits ifrepetitions of same digit on the six digit number is allowed is 1 000 000 numbers(including number 000 000).If no repetitions of the the same digit are allowed then you have:10P6 = 10!/(10-6)! = 151 200 different six digit numbers(six digit permutations form 10 different digits).

24 three digit numbers if repetition of digits is not allowed. 4P3 = 24.If repetition of digits is allowed then we have:For 3 repetitions, 4 three digit numbers.For 2 repetitions, 36 three digit numbers.So we have a total of 64 three digit numbers if repetition of digits is allowed.

Assuming all 45 digits are different (which they will not be if they are ordinary integers), then 456, if repetitions are allowed. That is 8303765625. If repetitions are not allowed then the number falls to 45*44*43*42*41*40 = 5864443200

2,401

10,000

They are called decimal digits.

There are 76 such numbers. Eight more if you allow numbers to start with 0.

5^4

27 three digit numbers from the digits 3, 5, 7 including repetitions.

10,000