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

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?

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

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

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

While house hunting in London, I came across a very good leasehold property Discussing the lease the landlady told me:

'The property was originally on a 99 years lease and two-thirds of the time passed is equal to four-fifths of the time to come. Now work it out for yourself and see how many years are to go!

Can you calculate the probability of getting a sum of six when a dice is thrown twice?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

You have a roll of cloth 1km long. You have a machine which cuts this roll into pieces of 10-meter-long cloth.

How long would it take for the machine to cut the roll if each cut took 4 secs?

What's a single-digit number with no value?