As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

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.

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

A girl rode into a tourist spot out of the city on Thursday. She loved the place and decided to stay for a few days. She stayed for four days and then she left for back home on Thursday.

How can this be possible?

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

What animal walks on four legs in the morning, two legs during the day, and three legs in the evening?

Oedipus, the king of Thebes, figured out the answer to the riddle:

Why do we preferably have round manhole covers and not square ones?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M