what does the below math rebus puzzle mean?

What always comes into a house through the keyhole?

What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.

What is the riddle which can be asked all day with a different correct answer each time.

Only Highly Attentive Can Spot The Ladder In This Library In 7 Seconds! Can You?

Two Twins Jack and Jill were standing back to back and suddenly they started running in opposite direction for 4 kilometres and then turn to left and run for another 3 kilometres.

what is the distance between the Baggio twins when they stop ?

Today, I celebrated my 32nd birthday but I was born in 1972.
How is this possible?

Suppose that you are trapped on the surface of a frozen lake. The surface is so smooth and ideal that there is no friction at all. You cant make any grip on the ice and no wind is blowing to help you out. You have just a mobile phone with you which has got no reception disabling you to call for help.

How will you plan your escape before you freeze to death on the frozen lake?

What has one eye, but can’t see?

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?