Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

A kind heart person buy packed food at 3$/packet from United states and sells them at 1$/packet at Africa. After some time he becomes a millionaire.

How come the guy become millionaire ?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

If 21x = 79x, what is the value of x?

Every words stands for unique digit that makes the arithmetic equation true

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

Which is Odd One Out and why?

4377

3954

9862

8454

9831

Which statement is true out of the following?
One statement here is false.
Two statements here are false.
Three statements here are false.

How can you take 2 from 5 and leave 4?