Question

How many 5 digit telephone numbers can be constructed using the digits 0 to 9?

Answer 1

Answer:

9*10*10*10*10 = 90000

Step-by-step explanation:

Required = 5 digit number.

So, At the leftmost place we have 9 options to choose from ( 1 to 9).

0 cannot be at the leftmost position, because then it would not be a 5 digit number,

Now, for the rest positions we can choose any number between 0 to 9. So, 10 options for each positions.

Hence, 9*10*10*10*10= 90000