Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

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

Can you place six X (crosses) in below board without making three in a row in any way ?

I’m orange, I wear a green hat and I sound like a parrot. What am I?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

Three fair coins are tossed in the air and they land with heads up. Can you calculate the chances that when they are tossed again, two coins will again land with heads up?

If Bihan is 10, Anirudha is 20, and Kim and Seal are both 5, but Rikold is 10, how much is Kenniger by the same trend?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?