Find the number of all numbers between 1000 and 10000 which have atleast one digit repeated.

Find the sum of all numbers between 200 and 400 which are divisible by 7.

Show that there are 4536 numbers between 1000 and 10000, which have none of their digits repeated. Of these, how many are odd numbers ?

Find the number of integers between 1 and 100000 having the sum of the digits 18.

Find the sum of all natural numbers lying between 100 and 1000, which are multiples of 5.

Find the sum of all natural numbers lying between 100 and 1000, which are multiple of 10.

How many numbers are there between 1000 and 9999 so that no digit is repeated.

How many numbers are there between 100 and 1000 such that at least one of their digits is 7 ?

Prove that there are exactly 4! numbers between 1000 and 10000 that contain the digits 1, 3, 5 and 7.

Find the sum of all natural numbers from 1 to 1000 which are not divisible by 5.