DiscussWorldIssues - Socio-Economic Religion and Political Uncensored Debate - View Single Post - Many calculators not following math rules?

**MatueHarton** · 11-04-2011, 08:25 AM

PEDMAS, BODMAS, BIDMAS or whatever you want to call isn't a mathematical axiom. It's a handy guide for remembering things but it shouldn't be treated as being a definitive rule. The correct way to do this is to sort out any operations in parentheses first (i.e. the 9 + 3) and then go back and read the expression left to right, where multiplication and division are done before addition/subtraction.

Thus the correct answer in Kaotika's original expression is 288 and not 2:

48 / 2 ( 9 + 3 ) = 48 ÷ 2 x 12 = 24 x 12 = 288

The answer is only 2 if the expression is specifically written like this:

48 / ( 2 ( 9 + 3 ) ) = 48 ÷ ( 2 x 12 ) = 48 ÷ 24 = 2

Slapping parentheses about can easily change an expression from its intended form.

But havn't you done it as if...

(48/2)(9+3) ...... Presuming there are extra brackets?

I'm not saying you're wrong, just wondering.

For me it all comes down to whether you do the multiplication or division first.

I think the answers 2 for the reason that what's in the brackets should be multiplied out first. But I think it's 288 by going left to right once the addition is done.

11-04-2011, 08:25 AM	#8
MatueHarton Join Date Oct 2005 Posts 546 Senior Member	PEDMAS, BODMAS, BIDMAS or whatever you want to call isn't a mathematical axiom. It's a handy guide for remembering things but it shouldn't be treated as being a definitive rule. The correct way to do this is to sort out any operations in parentheses first (i.e. the 9 + 3) and then go back and read the expression left to right, where multiplication and division are done before addition/subtraction. Thus the correct answer in Kaotika's original expression is 288 and not 2: 48 / 2 ( 9 + 3 ) = 48 ÷ 2 x 12 = 24 x 12 = 288 The answer is only 2 if the expression is specifically written like this: 48 / ( 2 ( 9 + 3 ) ) = 48 ÷ ( 2 x 12 ) = 48 ÷ 24 = 2 Slapping parentheses about can easily change an expression from its intended form. But havn't you done it as if... (48/2)(9+3) ...... Presuming there are extra brackets? I'm not saying you're wrong, just wondering. For me it all comes down to whether you do the multiplication or division first. I think the answers 2 for the reason that what's in the brackets should be multiplied out first. But I think it's 288 by going left to right once the addition is done.
	Quote