BODMAS question

11 Plus Maths – Preparation and Information

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SleepyHead
Posts: 484
Joined: Thu Oct 18, 2012 10:41 am

BODMAS question

Post by SleepyHead »

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
Tinkers
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Location: Reading

Re: BODMAS question

Post by Tinkers »

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.
SleepyHead
Posts: 484
Joined: Thu Oct 18, 2012 10:41 am

Re: BODMAS question

Post by SleepyHead »

Thank you :)
solimum
Posts: 1420
Joined: Wed May 09, 2007 3:09 pm
Location: Solihull, West Midlands

Re: BODMAS question

Post by solimum »

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
SleepyHead
Posts: 484
Joined: Thu Oct 18, 2012 10:41 am

Re: BODMAS question

Post by SleepyHead »

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
Surferfish
Posts: 682
Joined: Fri Mar 10, 2017 5:06 pm

Re: BODMAS question

Post by Surferfish »

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" onclick="window.open(this.href);return false;
SleepyHead
Posts: 484
Joined: Thu Oct 18, 2012 10:41 am

Re: BODMAS question

Post by SleepyHead »

That's really interesting - thank you
solimum
Posts: 1420
Joined: Wed May 09, 2007 3:09 pm
Location: Solihull, West Midlands

Re: BODMAS question

Post by solimum »

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 3:53 pm, edited 1 time in total.
yoyo123
Posts: 8099
Joined: Mon Jun 18, 2007 3:32 pm
Location: East Kent

Re: BODMAS question

Post by yoyo123 »

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" onclick="window.open(this.href);return false;
They should be familiar with that by year 6. Lots of maths vocabulary work from KS1 onwards
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