I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

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.

A father is locked up in jail. His wife has gone bankrupt. Their male child has to sell his hotel in order to gain some money. Yet their girl child does not care and is quite happy.

How can someone be so rude?

We have shown you a regular water barrel as below. Without using any measuring device can you check if the barrel is more than half-filled or less than half-filled?

Imagine you are in a room with no windows or doors. How will you get out?

Name a key which is hardest to turn.

Can you find the odd number in the following?

2716, 4135, 5321 and 7145

Can you divide the below-given shape into four equal and identical pieces?

If your uncle’s sister is not your aunt, what relation is she to you?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?