Can you do this simple maths problem?

[Roller123]

Hehehe operator precedence is defined by operator associativity. This is just stuff that comes later in school. Just wait till you learn that a*b is not always b*a.

What we have here is trying to apply the associative law to a/b*c, which would be (a/b)*c=a/(b*c), analogous with (a*b)*c=a*(b*c) but there is no law which proves it is possible. So far. lol.

multiplication and division have the same precedence (so are evaluated from left to right).

The second does not follow out of the first. And specifically in programming languages, some do it in reverse order. ...

 

[ParadigmShifter]

I have a degree in maths and work as a computer programmer...

I'm talking about standard operator precedence in mathematics anyway.

 

[Roller123]

I have a degree in maths and work as a computer programmer...

Interesting. This is stuff which is easily forgotten since its just pure math. I am a bit amazed that you believe in strict evaluation order, might be alcohol. (a+b-c) can be done in any order, really. ( (a+b)+c = (a+(b+c) ).

 

[ParadigmShifter]

But the precedence of multiplication and division are the same. Obviously if an operator is associative it doesn't matter which order you evaluate. If it isn't associative you evaluate from left to right (most of the time, not composition of functions nor power towers, for instance).

 

[CELTICEMPIRE]

48÷2(9+3) = ?

=2

 

[warpus]

As has been said, it's 288.

It would be 2 if the question read 48÷(2(9+3)) = ?

It makes more sense if you rewrite 48÷2(9+3) = ? as (48÷2)(9+3) = ?, which is what is going on

I took math in University at a fairly high level, and if there's multiple crap in the denominator and you use the ÷ or / symbol (which nobody does, but whatever), you need brackets. If you don't have brackets, not all of the things are in the denominator.

 

[ParadigmShifter]

Yes, or

   48
---------
  2(9+3)

 

[warpus]

Yes, or

   48
---------
  2(9+3)

Yeah, but that's 48/(2(9+3)), not 48/2*(9+3)

Without brackets, you divide first and multiply later. The (9+3) isn't in the denominator unless you explicitly specify that - with brackets (or by doing what you did)

 

[ParadigmShifter]

I know!

Shocking that some people don't know that multiplication and division have equal precedence anyway.

 

[Quackers]

48 / 2 * (9+3)
48 / 2 * 12
48 / 2 = 24
24 * 12 = 288

bidmas

 

[Roller123]

Obviously

Well but thats what the trick here is. To see that it cant be done in any order, in other words, the associative law not applying. Its not obvious to everyone...

 

[ParadigmShifter]

*golfclap* for Quackers, 2nd time lucky.

 

[ParadigmShifter]

Well but thats what the trick here is. To see that it cant be done in any order, in other words, the associative law not applying.

There is no trick...

 

[JollyRoger]

I know!

Shocking that some people don't know that multiplication and division have equal precedence anyway.

Go forth and multiply. United we stand, divided we fall.

 

[warpus]

I know!

Shocking that some people don't know that multiplication and division have equal precedence anyway.

Ah, you were agreeing with me. How boring

 

[Quackers]

pfft, i don't have a maths degree and i can do this...useless

 

[ParadigmShifter]

On your second attempt Quacks.

 

[JollyRoger]

pfft, i don't have a maths degree and i can do this...useless

With Sharia Law so firmly entrenched in the UK, it is no surprise you can so easily work with Arabic numerals.

 

[ParadigmShifter]

Which were invented in India.

 

[JollyRoger]

Which were invented in India.

Well, you Brits had to pick up the concept to fully assimilate into Indian society.