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

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

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 ?

You need to arrange three 7 and mathematical symbols to form number 1?

I want to fill my bucket using both cold and hot water.
I have two taps for both cold and hot water. The hot water tap fills the bucket in exact 6 hours and the cold water tap fills the bucket in exact 4 hours.
I turn both of them simultaneously but I forgot to turn off another tap which removes the water out of the bucket. This tap can empty the bucket in 12 hours.

How Long will it take to fill the bucket?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

What is next number in the pattern below:

131 517 192 123 ?

Two trains start at the same time, one from Bangalore to Mysore and the other from Mysore to Bangalore. if they arrive at their destinations one hour and four hours respectively after passing one another, how much faster is one train running than the other?

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

Solve below popular number sequence
314 159 265 358 979 323 846 ?