Find the number of odd positive three digit integers.

Find the number of all positive integers of 3 digits which are divisibleby 5.

Find the number of all the three-digit numbers in Hindu-Arabic System.

Find the number of all three digit natural numbers which are divisible by 9.

Let a_n denote the number of all n-digit positive integers formed by the digits 0, 1, or both such that no consecutive digits in them are 0. Let b_n= The number of such n-digit integers ending with digit 1 and c_n= Then number of such n-digit integers with digit 0. The value of b_6 is

Find the number of positive integers greater than 6000 and less than 7000 which are divisible by 5, provided that no digit is to be repeated.