Mathematics Question

Hans Tucker (Hans) · #1 24-07-2021, 06:02 PM

Ok .. please humour me on this. I always thought Mathematics was meant to be definitive ... but maybe not.

Using the methods you were taught at school provide an answer for the following, please no calculators easy enough to do in your head.

8÷2 (2+2)=

RB (Andrew) · #2 24-07-2021, 06:03 PM

16

Sunfish (Ray) · #3 24-07-2021, 06:33 PM

+1.
Parentheses first.
Then left to right I think.

Quote:

Originally Posted by RB

16

multiweb (Marc) · #4 24-07-2021, 06:36 PM

...

Hans Tucker (Hans) · #5 24-07-2021, 06:40 PM

Quote:

Originally Posted by multiweb

...

Well one of the two is against it .. the other decided to play.

DiscoDuck (Paul) · #6 24-07-2021, 07:10 PM

Quote:

Originally Posted by Sunfish

+1.
Parentheses first.
Then left to right I think.

16 "+ 1" would be 17

astro744 · #7 24-07-2021, 07:24 PM

The web is full of examples like this. Do this on an old calculator and you get a different answer to doing the calculation on a new calculator. Apparently the rules haves changed in modern times.

Note there should only be one answer but it is similar to a poorly written sentence in which the meaning is ambiguous. I first came across these problems on YouTube videos by Presh Talwalker from Mind Your Decisions. Lots of great math problems there. Enjoy!

https://mindyourdecisions.com/blog/

https://m.youtube.com/channel/UCHnj59g7jezwTy5GeL8EA_g

Here is a similar problem with an explanation.

https://m.youtube.com/watch?v=URcUvFIUIhQ

Another good math site PreMath at https://m.youtube.com/c/PreMath

Sunfish (Ray) · #8 24-07-2021, 07:27 PM

Ha. Good one.
BTW I was reading that the division sign should not be used in international mathematics notation.

Use the slash.

Quote:

Originally Posted by DiscoDuck

16 "+ 1" would be 17

GrahamL · #9 24-07-2021, 08:15 PM

Is it 1 ?.. from school i'm thinking 16 is right.

FlashDrive (Poppy) · #10 24-07-2021, 08:29 PM

16 ....as far as I can remember you do the numbers in the ( ) first.

so...2+2 = 4 .... then do the 8 divided by 2 = 4 .... you then multiply 4 x 4 = 16.

equals 16.

Col.

Hans Tucker (Hans) · #11 24-07-2021, 08:46 PM

When you apply the rule BODMAS (Bracket, Order, Division, Multiplication, Addition, and Subtraction) you get the answer 16 which I believe is the correct answer.

A term I have never heard of, PEMDAS (Parentheses, Exponents, Multiplication, Division, Addition, and Subtraction), is used by students in the US.

Sunfish (Ray) · #12 24-07-2021, 09:44 PM

I think that was levity. The answer is definitely 16

Quote:

Originally Posted by GrahamL

Is it 1 ?.. from school i'm thinking 16 is right.

Atmos (Colin) · #13 24-07-2021, 10:57 PM

The answer is 42, geez

mura_gadi (Steve) · #14 25-07-2021, 06:07 AM

Gee, I'm old, that was called order of operations when I was a kid...

2+2x2 = 6, is the basic intro one....

Steve

xelasnave · #15 25-07-2021, 11:58 AM

You use the fingers on your left hand first.
Alex

Stonius (Markus) · #16 25-07-2021, 12:06 PM

Well since we're talking about our workings anyway...

I was taught BODMAS

8÷2 (2+2)

Brackets first

=8/2 (4)

Division next
=4 (4)

Multiplication next
=16

I don't consider myself to be good at maths, but I believe this is how I was taught.

Markus

PKay (Peter) · #17 25-07-2021, 11:09 PM

This has already been worked out by a super computer.
The answer is 42...

Zuts · #18 25-07-2021, 11:46 PM

Not many people would use this notation as it is confusing

8÷2 (2+2)=

rather

8/2(2+2)

(8/2)(2+2)

16

Steffen · #19 26-07-2021, 01:14 AM

Quote:

Originally Posted by xelasnave

You use the fingers on your left hand first

Ah, but that’s local bias. On the northern hemisphere they use the fingers on the right hand first!

leon · #20 26-07-2021, 06:42 AM

The way i remember it is ( ) first = 4, then 8 divided by 2 = 4, then x 4x4 = 16.

Leon