The number of natural numbers less than 1000, in which no two digits are repeated is

The number of positive integers less than 1000 having only odd digits is

What is the number of natural numbers less than or equal to 1000 which are neither divisible by 10 nor 15 nor 25?

The number of natural numbers of two or more than two digits in which digits from left to right are in increasing order is

Find the number of natural numbers which are less than 2xx10^8 and which can be written by means of the digit 1 and 2.

Find the number of natural numbers which are less than 2xx10^(8) and which can be written by means of the digit 1 and 2 .

Find the number of natural numbers which are less than 2xx10^8 and which can be written by means of the digit 1 and 2.

Find the number of natural numbers which are less than 2xx10^8 and which can be written by means of the digit 1 and 2.