I’m tall when I’m young, and I’m short when I’m old. What am I?

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

How do you go from 98 to 720 using just one letter?

What is the largest number you can write with just 3 digits?

A man hijacks an aeroplane transporting both passengers(8 of them) and valuable cargo. After taking the cargo, the man demands nine parachutes, puts one of them on, and jumps, leaving the other eight behind. Why did he want eight?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

What numbers should go on the bottom line?
3 6 9 15
8 2 10 12
11 8 19 27
19 10 29 39
? ? ? ?

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

You have two buckets - one holds exactly 5 gallons and the other 3 gallons. How can you measure 4 gallons of water into the 5 gallon bucket?

(Assume you have an unlimited supply of water and that there are no measurement markings of any kind on the buckets.)

What is greater than gold but cannot be bought. it can never be sold and can earn if its sought. though it can be broken, it can still be fixed. for by birth it can't start nor by death it is ended.what am i?