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today i discovered that in Microsoft calculator Standard mode 4*3+4*3=48 . At least when you open History of calculations.

To me this is not acceptable, it is complete opposite from my complete 16 years of education, but apparently there are different kinds of people, seeing no problem with that. This formula is only correct if operator precedence is not followed.

This is part that i don't understand. Isn't modern math accepted and same in all around the world? Operations are associative and commutative? Or some different rules are applied in different countries?

I would appreciate some short explanation. Thanks

win10 calculator history

Ben Grossmann
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miki
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    To clarify "if operator precedence is not followed", the calculator interpreted the input as $$ ((4\times 3)+4)\times 3 $$ – Ben Grossmann Jun 28 '19 at 16:37
  • I wonder what operator precedence you would have to use for this to be correct. – Pink Panther Jun 28 '19 at 16:38
  • You might find this post and this post to be of interest. – Ben Grossmann Jun 28 '19 at 16:39
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    @PinkPanther standard order of operations ("PEMDAS") would yield $$ 4 \times 3 + 4 \times 3 = (4 \times 3) + (4 \times 3) = 24 $$ – Ben Grossmann Jun 28 '19 at 16:40
  • I know that it should be 24. I was wondering how to come up with 48 – Pink Panther Jun 28 '19 at 16:42
  • You are right! I didn't believe it so I tried it myself and got 48 instead of 24! The calculator is doing the calculations serially rather than using operator precedence: 43= 12, 12+ 4= 16, and then 163= 48.Oddly enough the scientific mode does it correctly. – user247327 Jun 28 '19 at 16:53
  • That's definitely an interesting discovery, Wow. Also, different countries don't have different rules -- that's impossible (well, they could try to come up with something different but it would most likely be wrong.). Different notation, maybe, but not different rules. – N. Bar Jun 28 '19 at 17:00
  • @N.Bar I am having some discusion on codeproject , so some answers really amazed me. I had to ask this silly question :D – miki Jun 28 '19 at 17:01
  • My biggest problem with this is that Microsoft displays equation wrongly in calculation History. So when you want to check equation to see if you typed everything correctly, you still can have wrong result. – miki Jun 28 '19 at 17:07
  • @miki You have to work with the memory of the calculator. But you´re right that the interpretation of the input is not state of the art. – callculus42 Jun 28 '19 at 17:39

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