If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth, I am dissolved into air. What am I?

What's the only room from which no one can enter or leave

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

Can you fill the blank with the correct number?

6 30 870 756030 _____

Count the squares in the matchstick puzzle below?

Can you find the missing piece of the Porsche?

Which wheel of car does not rotate when you turn your car right?

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

Chef Andrea has to light the kitchen stoves to open her restaurant for the day. There are three stoves in the kitchen: A glass stove, a brick stove, and a wood stove. She only has one match. Which does she light up first?