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

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

Two friends were stuck in a cottage. They had nothing to do and thus they started playing cards. Suddenly the power went off and Friend 1 inverted the position of 15 cards in the normal deck of 52 cards and shuffled it. Now he asked Friend 2 to divide the cards into two piles (need not be equal) with equal number of cards facing up. The room was quite dark and Friend 2 could not see the cards. He thinks for a while and then divides the cards in two piles.

On checking, the count of cards facing up is same in both the piles. How could Friend 2 have done it ?

How many triangles can you find in this given picture?

Can you count the number of seconds in a year?

Clue: You need to bother about calculation.

Can you find the six hidden animals in the picture below?

What brings you down but never up?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

Solve this logical number series puzzle by replacing the question mark with the correct number
9090 = 4
1234 = 0
6055 = 2
9081 = 4
8888 = ?

Can you count the number of squares in the figure below?

Can it be possible to build a house that has all its four walls facing towards the South?