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Maths experts how would you work this out using BODMAS?

20 replies

LilyTucker · 06/09/2015 10:52

20-10./.2+14

./. is my attempt at the division signSmile

Also could you talk me through it.

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DoreenLethal · 06/09/2015 10:56

Brackets - none
Of - none
Division - 10 divided by 2 = 5
So 20-5+14 = 39.

araminem · 06/09/2015 10:57

First dó 10/2=5. This leaves you with 20-5+14=29.

You first do the division bit than the addition/subtraction.

BeautifulBatman · 06/09/2015 10:59

20 -(10÷2)=15.
15+14=29.

MarietteL · 06/09/2015 10:59

29

LilyTucker · 06/09/2015 11:01

It's either 19,29,14,15 or 24

19 is wrong

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LilyTucker · 06/09/2015 11:03

Dp says that is wrong because it's addition before subtraction.

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LilyTucker · 06/09/2015 11:04

Also how do you choose where to put the brackets in?

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PosterEh · 06/09/2015 11:04

29

BeautifulBatman · 06/09/2015 11:04

DP says what is wrong? I'm no 'expert', but I do teach maths. 29 is the right answer.

PosterEh · 06/09/2015 11:07

You put the brakets around the bit you do first. So using bodmas the division is first in that equation so you can put brackets round the division of it makes it easier to see what is going on (you don't need the brackets because bodmas tells you what to do first but it can make it easier to see).

capricalia · 06/09/2015 11:07

Brackets would be before the 10 and after the 2 as far as I remember

Additional and subtraction usually done at the same time - it's been a while.

Huntthepigsear · 06/09/2015 11:07

Addition and subtraction are both third order sums, so should be done left to right.
29 is correct.

LilyTucker · 06/09/2015 11:09

Cool,got to fly will go over it later.

Many thanks,that's a great help all.

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SevenSeconds · 06/09/2015 11:09

You don't choose where to put the brackets - there are no brackets in this sum. If there were you'd do them first.

DoreenLethal · 06/09/2015 11:13

Sorry - slip of the finger 29!

Not 39

BeautifulBatman · 06/09/2015 11:13

Sorry - I put the brackets in to demonstrate the operation that had to be done first before the rest of the operations were completed.

OhYouBadBadKitten · 06/09/2015 11:13

10/2 first and then the rest doesnt matter because its just adding and subtracting. So the answer is 29.

The O stands for order, but it doesnt mean order of which way round you do things, its the same as Indices (so squares and cubes)

OhYouBadBadKitten · 06/09/2015 11:16

Remember that all adding and subtracting is, is moving up and down a number line, adding you are moving up, subtracting you are moving down. That is why it doesnt matter which one you do first out of the two. To see it, write yourself out a number line from -30 through 0 to +30 and have a play :)

addictedtosugar · 06/09/2015 11:16

It doesnt matter if you add or subtract first.
Division first ( unless the line goes all the way over the 2+14). So get
20-5+14.

Then it doesn't matter if you do 20+14, and take the 5 away, or if you take 5 from the 20, then add the 14, you still get 29.

Unless DH is putting brackets to make it read 20-(5+14), which is completely changing the mathematical sentance to 20-5-14.

dementedpixie · 08/09/2015 19:31

You do multiplication/division first and then work your way from left to right doing the addition and subtraction.

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