If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

What is the word or phrase below?
R | E | A | D

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

I know a nine-letter word having only one vowel.
Do you ?

Can you divide the below-given shape into four equal and identical pieces?

You have 10 balls with you. A friend of yours out of nowhere asks you to place those ten balls in five lines such that each of the lines has exactly 4 balls on them. He needs to check your intelligence. Prove him by doing the task.

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?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?