Question

How many 5-digit numbers can be formed using the digits 0,1,2,3,4,5,6, if repetition of digits is not allowed?

Answer 1

Answer:

Is it 2160?

Step-by-step explanation:

This is permutation

Imagine □□□□□, each □ represents a digit

For the 1st □, there are 6 choices, since "0" cannot be the first digit, or else it is not a 5-digit number

For the 2nd □, there are 6 choices (1 out of the 7 number is already used)

For the 3rd □, there are 5 choices (2 out of 7 numbers are used)

And so on.....

Therefore,

6×6×5×4×3 = 2160