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

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

A game is being played where eight players can last for thirty-five minutes. Six substitutes alternate with each player in this game. Thus, all players are on the pitch for the same amount of time including the substitutes.

For how long is each player on the pitch?

You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?

Can you solve this picture maths equation?

I am under you when I am whole.
I shift above you if you remove the first letter.
I come all around you if you remove the second as well.

Can you tell me who I am?

What can you see in the middle of March and April that you can never see in any other month?

Can you name some countries which do not have the alphabet 'A' in them?

One night, a woman receives a call from the police. They tell her that her husband was murdered and that she should come to the crime scene as soon as possible. The woman drops the phone, shocked, and drives 20 minutes to the crime scene. As soon as she reaches the crime scene, the police arrest her and she is convicted of murder. How do the police know she committed the crime?

Can you find out which number multiplied by itself will give the output as 12345678987654321?