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

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

I never was there, I am always to be.
You have never ever seen me, not ever you will.
Yet I am the confidence of everyone.

Who Am I?

If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

What can you catch but never throw?

Find the number of squares in the below-given picture.

A man started to town with a fox, a goose, and a sack of corn. He came to a stream which he had to cross in a tiny boat. He could only take one across at a time. He could not leave the fox alone with the goose or the goose alone with the corn. How did he get them all safely over the stream?

Decode below rebus
D
N
A
T
S , D

What is the next shape from answers A, B, C, and D figure?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

I am a ten letters word
The first four letters have the power to rule,
Next, four-letter can be eaten.
The next three-letter represents a lady.
I can fly as well

what am I looking for?