If I have 10 numbers [ 0-9 ], how many 4 digit combinations can I make, and how is this solved?

Answer 1

first digit : 10 choices
second digit : 9 choices
third digit : 8 choices
fourth digit : 7 choices
Thus you can make 10*9*8*7 different numbers.

Answer 2

Hmmm I think the answer is 10000 if you are looking for combinations but 9000 if you are looking for the 4 digit numbers.

If you are looking for 4 digit numbers then you have 9 digits to choose from for the first place (a 4 digit number can't have a leading zero), and the remaining 3 places can be chosen from any of the 10 digits (because the digit can repeat). Thus different numbers that can be created using digits 0-9 = 9*10*10*10 = 9000.

For combinations - of course you don't have to worry about not having a leading zero - ie you have 10 options for the first spot too, therefore different combinations - 10*10*10*10 = 10000

Answer 3

if you do not mind having 0 upfront(as having 0upfront will render the number a three digit number 0 then 4 digit combinations=10*9*8*7=5040 all dissimilar
having all the four digits same=10*1*1*1=10
having any two digits similar will be 6(10*1*9*8)=4320
having any three digits similar will be =4(10*1*1*9)=360
adding up the total will be=9730
however if the digits can also repeat it will be=10*10*10*10=10000

Answer 4

First digit has 10 values. Likewise all the remaining digits.
10 x 10 x 10 x 10 = 10^4 = 10000 combinations

Answer 5

You find the answer out by multiplying 10x9x8x7

Because you have 10 numbers you start with 10 and because you only want 4 digit combinations you go down only 4 numbers. This is assuming that a combination can be 1111, 1222, 1122, etc. Repeating numbers.

If you only want each number to be represented once such as 1234, 4321, etc then you should multiply 4x3x2x1.

Answer 6

10000.
Every number between 1-9999 is a 4 digit combination. Single digits are expressed with leading zeros. Add in 0000, and that's 10000 combinations.

Answer 7

For first digit we have 9 choices because a number cant start with 0
For second digit also we hv 9 choices left
For third digit we hv 8 choices
For last didgit we have 7 choices.
So 9 x 9 x8 x7
= 4536

Answer 8

10*9*8*7 bc whn u pick the 1st number, you hve 10 numbers to choose from, the 2nd is from 9 numbers, nd so on, until you hve 4 digits

Answer 9

10C4 = 10!/(4!6!) = 7*8*9*10/6 = 5040/6 = 840

You choose 4 numbers out of 10

Answer 10

10000 there are four slots each with ten possible values so there are 10 to the fouth possibilities.