How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

What can go up a chimney down, but can’t go down a chimney up?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

What does below pictogram mean?

Using Only Five 5's and any mathematical operator make sum as 37

A few friends are enjoying their sea voyage in a boat full of apples. On the way, they felt hungry and thus decided to eat the apples. Together, they ate two dozen of apples. When they have eaten the apples, will there be any change in the water level?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

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

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?