Can anyone say why 8-12+9=5?

Posted:: 3+ months ago by Qwertypoi...
Topics:: first, thought, teacher, addition

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I thought it would be -13 but my teacher said it's wrong. How is it 5 if In BODMAS addition comes first? Shouldn't it be 12+9= 21 and then 8-21= -13???

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Answers (1)

PhiBonacci

What miracle changed 21 ( in 12 + 9 = 21) into -21 ( in 8 - 21 = -13) ???

You've got three numbers:

8, -12, 9

8 + -12 + 9 = 5

-12 + 9 + 8 = 5

If you want to add first:

9 + 8 + -12 = 5.

It works either way, but DON'T meddle with the signs!

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FauxPas

Seems to have given precedence to addition over subtraction, ie 8 - (12 + 9).

Addition & subtraction are equal in order. Above (before) them are multiplication & division. Above all parentheses.

FauxPas

Seems to have given precedence to addition over subtraction, ie 8 - (12 + 9).

Addition & subtraction are equal in order. Above (before) them are multiplication & division. Above all parentheses.

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