Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

What is next number in the pattern below:

131 517 192 123 ?

John is pretty weird. He likes toffees but hates chocolates. He loves books but never reads. He likes to build his troops in an online game but does not proceed with the war. He likes to go swimming but is afraid of water.

Seeking this behaviour, can you tell whether he likes balloons and parties?

I am five letter word that is under you.
If you remove my 1st letter, then I am over you.
If you remove my 1st and 2nd letters then I am all around you.

Who am I?

Can you write down eight eights so that they add up to one thousand?

A man was gazing through the window of the 23rd floor of the building. He suddenly opened the window and jumped on the other side of the window. On landing on the floor, there was not a sheer mark of injury on him.

How can that be possible if he did not use any kind of parachute and did not land on a soft surface?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

I add 5 to 9 and get 2. The answer is correct, so what am I?

How can you leave a room with two legs and return with six legs?

Find the mistake in the below maths equations

A = 2
A(A-1) = 2(A-1)
A2-A = 2A-2
A2-2A = A-2
A(A-2) = A-2
A = 1