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

During which month do people sleep the least?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

How is a fly different from a mosquito?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

When a clock is observed, the hour hand is at a minute mark and the minutes hand is six minutes ahead of it.

When the clock is observed again after some time, the hour hand is precisely on a different minute mark and the minute hand is seven minutes ahead of it.

Can you calculate how much time has elapsed between the two observations?

Count the number of balls in picture below:

Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?