Any six-digit number that is formed by repeating a three-digit number, is always divisible by:

Find the greatest number which divides 108, 124 and 156, leaving the same remainder. 

How many numbers are there from 500 to 650 (including both) which are neither divisible by 3 nor by 7?

Find the greatest number 23a68b, which is divisible by 3 but NOT divisible by 9.

The difference between a number and the square root of the number is 2. The number is:

Select the number triad that is analogous to the given triads.
 (64, 8, 65), (125, 27, 89)

What is the sum of all three-digit numbers which are divisible by 20?

Select the set in which the numbers are related in the same way as the numbers of the following set.
 (12, 30, 204)