a mathematical mystery

[Blunt]

all hail the arcticfire brainiac:worshippy:

[Hektor]

i also told this riddle to several math teachers. they all agreed, that this way of calculation doesnt breack any mathematical law.
they studied math so i supposed that they were right, but...
... im not an expert with math and also the teachers can be wrong, so there is no guarantee i can give for the truth of this enigma.
you all think there is a logical mistake?... well, when there is one, i apologize to you all for wasting your time :crying:



PS: maye itll be useful to ask a math professor or someone with a very deep mathematical knowledge if this way of calculation breaks any       mathematical law.

[Bob]

so there is no guarantee i can give for the truth of this enigma.

I'll just, a bit freely, quote The Matrix: There is no enigma
I'll just repeat what I, and several others in different ways, already have said:

30 - 3 + 2 will never be 30, everyone can tell that. You just managed to "hide" that that was the actual calculation :learn:

well, when there is one, i apologize to you all for wasting your time :crying:

And no worries - there is quite much other useless crap going on in this forum, so a small mathematical brain refresher every now and than isn't a waste at all :flirty:

[T-Bag]

It's quite interesting, this shows how a brain works more than a flaw in maths as a whole. If you tell someone to look at a problem a certain way they can get puzzled.
The £27 is the £25 + £2. But if you tell them £27 and the £2 the waitress took doesn't equal 30 they'll follow that path. (It won't equal £30 because they were paid back £1 each)
You lead someone on to thinking the £2 is whats not been acounted for, rather than the £3 that they've already taken back.

As soon as you realise either the meal only cost £25 and they paid £27, or they paid £30 but got £3 back. It's all clear.