What number do you get when you multiply all of the numbers on a telephone's number pad?

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?

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

If you had an infinite supply of water and 5-quart and 3-quart pails, how would you measure exactly 4 quarts? What is the least number of steps you need?

There are two dice with empty faces in front of you and a marker. You can mark any number on each of the faces of the two dice, but you have to display all 31 days of the month using the two of them.

Which numbers will you mark on which dice so that you can easily depict all the dates of the month?

Can you place six X (crosses) in below board without making three in a row in any way ?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?