What happened when the wheel was invented?

What is always in front of you but can’t be seen?

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

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

Complete the table series riddle by finding the number that can replace "??".

In the picture given below, can you find out which digit will take place of the question mark?

How high do you have to count before you use the letter “a” in the English spelling of the whole number?

John and Jill are madly in love with each other. To remind Jill of his pure love, John wants to send her a ring by post but in their country where burglary is quite prominent, any package that is not locked comes under the risk of being stolen for the contents.

John and Jill possess many padlocks but neither one of them has the other key.

Can you find a way John can send the ring to Jill safely?

There were five men at church, and it started raining while they were outside. The four that ran still got wet, but the one that was still stayed completely dry. Why did he stay dry?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?