if accounting systems are perfect how do we have so many scams?

Question

why is it that they do not teach practical accounting in the school levels itself instead of giving so much prominance to history and geography

Answer 1

No system is fool proof for a sufficiently talented fool.

Also, there are always people who think they are smarter than the system, and for a while they are. Some don't ever get caught, some get greedy or careless and do get caught.