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 Post subject: BODMAS question
PostPosted: Wed May 20, 2020 10:22 am 
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Joined: Thu Oct 18, 2012 9:41 am
Posts: 482
Hello all,

Please could someone help with the question below:


12 - 2 x 4 + 3

Answers are:
A: 7
B: -2
C: 43
D:70
E: 1

I made it 7 and DS made it 1 !

My reasoning: 12 - 8 + 3
Doing 12 + 3 first = 15
Then 15 - 8 = 7

DS said: 12 - 8 + 3
Doing the addition first
8 + 3 = 11
12 - 11 = 1

Thank you
Sleepyhead


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 Post subject: Re: BODMAS question
PostPosted: Wed May 20, 2020 11:01 am 
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Joined: Mon May 16, 2011 1:05 pm
Posts: 6841
Location: Reading
7 is correct.

Your DS should be doing -8+3 of he feels he needs to do the addition first before subtraction, however he doesn’t need to. BODMAS puts the D and M toegethr and the A and S Together.


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 Post subject: Re: BODMAS question
PostPosted: Wed May 20, 2020 11:15 am 
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Joined: Thu Oct 18, 2012 9:41 am
Posts: 482
Thank you :)


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 Post subject: Re: BODMAS question
PostPosted: Wed May 20, 2020 11:33 am 
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Joined: Wed May 09, 2007 2:09 pm
Posts: 1202
Location: Solihull, West Midlands
Tinkers wrote:
7 is correct.

BODMAS puts the D and M together and the A and S Together.


yes: within D&M and within A&S it's from left to right


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 Post subject: Re: BODMAS question
PostPosted: Wed May 20, 2020 12:00 pm 
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Joined: Thu Oct 18, 2012 9:41 am
Posts: 482
solimum wrote:
Tinkers wrote:
7 is correct.

BODMAS puts the D and M together and the A and S Together.


yes: within D&M and within A&S it's from left to right



thank you - that helps


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 Post subject: Re: BODMAS question
PostPosted: Wed May 20, 2020 1:58 pm 
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Joined: Fri Mar 10, 2017 4:06 pm
Posts: 682
Yes the correct answer is 7 as explained.

This question is a great example of the biggest pitfall of the BODMAS mnemonic which seems to imply that division comes before multiplication and addition comes before subtraction. As others have mentioned though this is incorrect. The only reason that its BODMAS rather than BODMSA, BOMDAS or BOMDSA is that the former trips off the tongue better!

Interesting article here that suggests that pupils would be better served by the acronym BOPS where the P stands for Products (* and /) and the S stands for Sums (+ and -). The downside is that Product and Sum are perhaps less familiar terms for younger children.

https://www.teachwire.net/news/why-its- ... bin-bodmas


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 Post subject: Re: BODMAS question
PostPosted: Wed May 20, 2020 3:07 pm 
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Joined: Thu Oct 18, 2012 9:41 am
Posts: 482
That's really interesting - thank you


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 Post subject: Re: BODMAS question
PostPosted: Thu May 21, 2020 8:54 am 
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Joined: Wed May 09, 2007 2:09 pm
Posts: 1202
Location: Solihull, West Midlands
I knew my instinct to despise BODMAS was well-founded - BOPS it is from now on....


Last edited by solimum on Thu May 21, 2020 2:53 pm, edited 1 time in total.

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 Post subject: Re: BODMAS question
PostPosted: Thu May 21, 2020 10:51 am 
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Joined: Mon Jun 18, 2007 2:32 pm
Posts: 7655
Location: East Kent
Surferfish wrote:
Yes the correct answer is 7 as explained.

This question is a great example of the biggest pitfall of the BODMAS mnemonic which seems to imply that division comes before multiplication and addition comes before subtraction. As others have mentioned though this is incorrect. The only reason that its BODMAS rather than BODMSA, BOMDAS or BOMDSA is that the former trips off the tongue better!

Interesting article here that suggests that pupils would be better served by the acronym BOPS where the P stands for Products (* and /) and the S stands for Sums (+ and -). The downside is that Product and Sum are perhaps less familiar terms for younger children.

https://www.teachwire.net/news/why-its- ... bin-bodmas

They should be familiar with that by year 6. Lots of maths vocabulary work from KS1 onwards


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