A four digit number is formed by writing a two digit number together twice like: 15:15, -3737 etc. A number of this form will be exactly divisible by which of the following numbers 

If the 5-digit number 535ab is divisible by 3, 7 and 11, then what is the value of (a² - b² + ab)?

The greatest 4-digit number which is a perfect square is

A man spends  $${1\over 3}$$ of his income on food,   $${2\over 5}$$  of his income house rent and   $${1\over 5}$$ of his income on clothes. If he still has Rs. 400 left with him, his income is: 

The real number to be added to 13851 to get a number that is divisible by 87 is :

Find the least number which when divided by 12, 15, 18 and 27 leaves remainders 10, 13, 16 and 25 respectively.

The value of (81)3.6 * (9)2.7/ (81)4.2 * (3) is __

For which value of x the seven-digit number 8439x53 is divisible by 99?