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

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

There are two insects on a tile. Insect X is sitting on one side of the tile (point A) and Insect Y is sitting opposite on the other side of the tile (point B). Now both of them decide to change their position and thus X starts crawling to point B and Y starts crawling to point A. When they meet and pass each other in between, X takes 20 seconds to reach B and Y takes just 5 seconds to reach A.

Can you calculate the total time each of the insects took to change their positions?

Replace the 'X' with any mathematical symbol to make the expression equal to 111.

18 X 12 X 2 X 3 = 111

What number divided by 4 is the same as that number minus 4?

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

Find out the missing number in the picture attached:

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?