# BODMAS debate

Discussion in 'Mathematics' started by arsinh, Apr 8, 2011.

1. ### arsinhNew commenter

I think you've managed to confuse yourself in your haste here and then failed to understand why valed was surprised.
They are but surely any ambiguity can be removed by using extra brackets (or latex)?

2. ### NazardNew commenter

I agree with this.
3a/2b might mean
<u>3a</u>
2b
(as a fraction).
3a/2b might mean 3<font size="3" face="Calibri">&times;a</font><font size="3" face="Calibri">&divide;2&times;b, in which case BODMAS should probably apply (unless the author is being a little sloppy).</font>
<font size="3" face="Calibri">The problem here is not one of the meaning of BODMAS or even the interpretation of it, but of people not writing clearly.</font>
<font size="3" face="Calibri">If anyone is really interested in pursuing this, reading the 157 posts in this thread might cure you!</font>

3. ### D Franklin

I don't know that I confused myself, but I certainly managed to miss the typo! Thanks.

4. ### valed

That is why we need an edit option on this forum - to address those inconvenient little errors that we make.
Embarrassing innit?

5. ### D Franklin

Not really, I'm sure I've made much more embarressing mistakes than that before!

Genius !

7. ### FlippantFlyer

When teaching precedence of operations l use an identity like:
<u>a+b</u> is equivalent to (a+b) <font size="2">&divide; (x-y) </font>
x-y
to preserve the consistency of BIDMAS/BODMAS, and no, <font size="2" face="Trebuchet MS">that isn't BIDMAS divided by BODMAS! That slash sign has a lot to answer for!</font>

9. ### Betamale

I am with Frustum on this
D Franklin
I like this debate.
My concern is the debate you are having is on TSR and you know there are some clued up people but also many kids who are often not mature in their posting/debates which leads to digging in and often debating for debatings reasons

10. ### FlippantFlyer

I think the bottom line (no pun intended) is that if you want to write a fraction on a single line with a slash or division sign then you should include brackets to maintain strict form and prevent ambiguity, however superfluous it looks ie 2x/2y should be written (2x)/(2y) if it was intended to be '2x over 2y.'

11. ### bolzanoweierstrass

I agree with you: 3x and 2y are both algebraic terms, so there is only one operation - a division of one term by the other - and therefore no need to resort to Bodmas.

12. ### siddons_sara

Agreed, doesn't seem ambiguous from the discussion given at the link above. Also, as is standard practice in such matters, I defer to 'mathsisfun.com', and they agree, multiplication and division have equal precedence and read from left to right.

It is, therefore, necessary to use parentheses on occasions.

FlippantFlyer, why would we ever write (2x)/(2y)? Isn't this just x/y? Or am I missing something?

13. ### siddons_sara

Using the rules from Dr. Math and mathsisfun.com

3x/2y = (3xy)/2

Since giving multiplication and division equal precedence and reading from left to right gives:

((3x)/2)y

Is it BODMAS itself that causes confusion by implying that division has greater precedence than multiplication? When in fact when both are written on the same line, we read from left to right.

?

?

16. ### FlippantFlyer

Sorry, I meant to type (3x)/(2y)!
Here's a fanciful idea. What if we introduce another operator symbol (such as &not to mean everything on the left divided by everything on the right. We could then dispense with the cumbersome brackets to have 3x&not;2x without ambiguity! . . . Oh well just a thought

17. ### FlippantFlyer

If we rewrite with the implied operators then we have 3 x X/2 x Y and could argue that X/2 is an algebraic term.

18. ### murkleNew commenter

Interesting answer to the question from Wolfram Alpha

http://www.wolframalpha.com/input/?i=3x%2F2+y

http://www.wolframalpha.com/input/?i=3x%2F2y

19. ### Vince_UlamStar commenter

This is a debate worthy of Wonderland.
To fret over implied multiplication is as pointless as to fret over implied addition.

20. ### bolzanoweierstrass

Quite right, Vince, how dare someone ask a question in an open-minded way and provoke some debate? What do they think this is, some sort of forum?