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

What is the largest number you can write with just 3 digits?

What is next number in the pattern below:

131 517 192 123 ?

Rectify the following equality 101 - 102 = 1 by moving just one digit.

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

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

How many triangles are there on the puzzle below?

Chocolate costs 6 rupees and a Toy costs 5 rupees. If you have 32 rupees in total, how many chocolates and how many Toys can be purchased with that amount?

Find the combined weight of the Cat, Dog and Rabbit in the given picture.