What is the next number in this series?

4,12,84,3612....

Prove that twice of ten is the same as twice of eleven.

Use the digits from 1 up to 9 and make 100.

Follow the rules.
=> Each digit should be used only once.
=> You can only use addition.
=> For making a number, two single digits can be combined (for example, 4 and 2 can be combined to form 42 or 24)
=> A fraction can also be made by combining the two single digits (for example, 4 and 2 can be combined to form 4/2 or 2/4)

Question: how can we do this?

How many times in a given day, minutes and hour clock comes in a straight line ?

If a wheel has 54 spokes, how many spaces are there between the spokes?

While preparing the table for dinner, wife came up with an idea to tease his mathematician husband. She asked her husband to pick nine toothpicks and make ten without breaking any toothpick.

The husband was also smart and did it within seconds. How ?

A Shopkeeper collects 71 rupees in the form of 20 paisa and 25 paisa.
He collects a total of 324 coins.

Can you tell me how many number of 20-paisa and 25-paisa he got?

I have teeth but i don't bite. Who Am I ?

A father's child, a mother's child, yet no one's son.

Who am I?

What is more useful when it is broken?