[Misc] Bodmas

[Kalimantan Gull]

One for the nerds and mathematicians out there.

Simple equation. 20+4x4

Deliberately no brackets. Type that with an = in front in Excel and you get what it, to me, the correct answer, 36. Mrs GB insists it is 96 because that's what you get when you type it into a calculator - obviously this is because the calculator is doing one sum after the other and you HAVE to use the brackets to define operational order on a calculator.

The issue being she says she was never taught this at school and has an A in her O Level Maths and I'm pretty sure I wasn't either.

So, the question is, when did BODMAS come in and is it a hard and fast rule? Or a modern concept that relates to spreadsheets and calculators? Or am I either a) too old to remember or b) taught with outdated methods? Son was apparently learning it in year 7 so maybe those GCSEs aren't so noddy.

BTW this also extends to English. I was certainly never taught what a "fronted adverbial" was and yet it's one of the things I have to help my daughter with during the lockdown.

Is a funny one, I got 100% in my maths A level in '92 and I hadn't heard the phrase BIDMAS until about 3 years ago, I just don't think they taught it in the late 80s. I would also quite happily say the answer was 96 - despite knowing that multiplication does take priority it wasn't taught quite so hard and fast. Basically we always used brackets for everything, so it would be written 20 + (4x4). I think this must be because of the introduction of scientific calculators at this time where if you typed in 20+4x4 before pressing =, the result would be 96. So to avoid conflict between teachers and calculators we use brackets to avoid confusion.

 

[Harry Wilson's tackle]

Crikey! MY Maths teacher in 1970 (I was 14) was also a Mr Thomas. Could it be the same one or is it a common surname for Maths teachers? Mind you, my Mr. Thomas was a Maths MASTER rather than teacher at my somewhat traditional Wealden school!

That would have had to be serious moonlighting, as David Bowie might have it.

Actually perhaps Thomases are good at maths and moonlighting. There was one at the Albion who worked out how to sit on a contract for three years, collect his money, and spend most of his 'spare' time working as a DJ.

 

[LlcoolJ]

I love NSC.

This answer has been dissected, discussed sensibly and clearly and explained so that a small child could understand it (most of them do these days).

And yet STILL some people are GETTING it wrong.

 

[wardy wonder land]

Downlands Hassocks from '81 to '86

BoDMAS definatly a thing, i have always remebered it as Brackets OVER Division, multiplication, Addition, subrtaction

the other was " i went TOA SOH-CAH match"

 

[Brightonfan1983]

Just ordered a free sample of this. Sounds good, thanks for the tip.

Hope you like it after that medium-sized sell!

 

[Arthritic Toe]

NB I say the answer to the original question was 96, because there were no brackets

NB - you'd be wrong.

 

[ConfusedGloryHunter]

I love how people are debating fundamental rules of mathematics like there is a choice. This magnificent belligerence in the face of plain facts is what got Britain through the blitz and kept BHA going through the homeless years!

However, this thread also leads me to suspect that I may not find the answer to all the big questions in life on the pages of NSC after all. A pity as I am half way through reading the Brexit thread to learn how that got resolved satisfactorily for everyone.

 

[Herr Tubthumper]

I love NSC.

This answer has been dissected, discussed sensibly and clearly and explained so that a small child could understand it (most of them do these days).

And yet STILL some people are GETTING it wrong.

This is exactly how I feel after I have explained the errors of a Tory’s ways.

 

[Pogue Mahone]

That depends whether you write
What is 20, +4×4. ....or What is 20+4,×4....

Such is the importance of punctuation.

NB I say the answer to the original question was 96, because there were no brackets

It doesn't need brackets!

BODMAS tells you that in a number sentence, multplication must be done before addition (Brackets, Order, Division, Multiplication, Addistion, Subtraction). There are no brackets, no numbers with an 'order', so multiplication is next in line. No punctuation nexessay.

The answer is 36. It really is that basic.

 

[Mannakin]

https://en.wikipedia.org/wiki/Order_of_operations

To paraphrase:
For example, in mathematics and most computer languages, multiplication is granted a higher precedence than addition, and it has been this way since the introduction of modern algebraic notation.[1][2] Thus, the expression 2 + 3 × 4 is interpreted to have the value 2 + (3 × 4) = 14, not (2 + 3) × 4 = 20. With the introduction of exponents in the 16th and 17th centuries, they were given precedence over both addition and multiplication and could be placed only as a superscript to the right of their base.

I learned it this way in O-Level arithmetic and I'm 60 years young

i.e. 36

 

[OzMike]

In English, it's down to pauses...

You could say twenty plus <breathe> four times four and get one answer or say twenty plus four <breathe> times four and get a different answer.

Which is why Maths, which has no room for ambiguity, there must be rules to avoid this.

Works for me and I have a Batchelors in Mech Eng.

 

[OzMike]

In English its entirely ambiguous. It can be 96 or 36. In Maths it is 36. Maths has additional rules which English doesn't have.

I was taught the order of precidence in O level maths, but no one ever mentioned Bodmas. In my view its far more complicated to learn the acronym and remember what every letter stands for than it is to just learn the order of precidence.

Works for me and I have a Batchelors in Mech Eng.