You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

If your uncle’s sister is not your aunt, what relation is she to you?

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

f you were running a race, and you passed the person in 2nd place, what place would you be in now?

what does the below math rebus puzzle mean?

If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

Which digit occurred maximum times between the number 1 and 1000?

If 24H in a D => 24 hours in a day.
What does "64S on CB" stand for?

Using the clues below, what four numbers am I thinking of?

The sum of all the numbers is 31.
One number is odd.
The highest number minus the lowest number is 7.
If you subtract the middle two numbers, it equals two.
There are no duplicate numbers.

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