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

There is a box in which distinct numbered balls have been kept. You have to pick two balls randomly from the lot.

If someone is offering you a 2 to 1 odds that the numbers will be relatively prime, for example
If the balls you picked had the numbers 6 and 13, you lose $1.
If the balls you picked had the numbers 5 and 25, you win $2.

Will you accept that bet?

When can we add 2 to 11 and get 1 as the correct answer?

What is the word or phrase?

Speaking of rivers, a man calls his dog from the opposite side of the river. The dog crosses the river without getting wet, and without using a bridge or boat. How?

Spot 5 differences in two Christmas tree below:

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

What makes this number unique: 8,549,176,320?

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?

Which flower has two lips?