The sum of all odd numbers from 1 to 41 is :

The sum of first 45 natural numbers is:

Find the sum of all three-digit numbers divisible by 9.

What is the sum of all the divisors of 256?

How many times the digit 9 occurs in the numbers from 100 to 999?

The difference between the squares of two numbers is 256000 and the sum of the numbers is 1000. The number are