Different outputs when using numerics vs variables

Questions
1

Hello. This is my first post. I’m sorry if I’m either posting it incorrectly, or posting about something I
shouldn’t be.
If this is somewhere here already, then I don’t know enough to know what to search for to find my answer.

Ok… Please don’t sigh, and hear me out…
6÷2(1+2) I know, Eww. Right?
My question is why does Wolfram process the following differently than if it’s in numerical form?

a÷bc, a=6, b=2, c=(1+2) or transpose c=3 if that’s the correct format.
I don’t want to know if you think it’s 1 or 9. I don’t want to know if you think it’s ambiguous.
I’m asking why with numbers it gives me one answer, but with variables it gives a different answer.
Is there a Convention I’m not thinking of that explains it? Is it some Computer Programing thing?
What did I do wrong?

Thank you for your time.

2

It would be helpful to know what result you actually got. Also, it would help us if you use the formatting tools to show exactly what you input.

I’m assuming that you didn’t have a space between the b and c.

a = 6;
b = 2;
c = (1 + 2);

a/b c
(* 9 *)

a/bc (* notice no space *)
(* 6/bc *)
3

Thank you for your response.
I apologize, I thought I had attached a picture to my first post with the results.
You were correct in your assumption that no space was added between b and c. The only spaces I’ve used are after the commas between the variable definitions.
I did both of these in Natural Language mode.
To get the Obelus “÷” I used Alt+0247. I used an Obelus instead of the “/” as that’s what the
original numerical problem used. * I do understand that ÷ isn’t really used anymore, but I was attempting to stay as accurate to the original as possible *

Thank you for taking the time to help me understand what I hope is just an error in my Input that I’m not grasping.

Question.png
Question.png776×718 32.9 KB

4

Natural Language mode uses the Wolfram|Aplha interpreter. That in turn uses a different precedence convention for the ÷ (obelus) than is used by the Wolfram Language (maybe also for the slash division sign, I’m not sure). All part of the the perils of trying to second-guess what the user intended.

5

Thank you. I appreciate what you’re saying. Since my first post I’ve repeated the results by using “/” instead of “÷”. The results are the same. It is giving a different result (and a different formulation) when using variables in place of numerals. I’ll see what I can find on the Wolfram|Aplha interpreter, and read up on it to see if I can find my answer. Thank you for your time.

6

Sometimes, if you experiment a little bit with inputs to Wolfram Alpha, you can find a syntax that Wolfram Alpha will show you an “Input interpretation” below your input that matches what you want.

Example: I found

a/b c where a=6, b=2, c=(1+2)

seems to be understood and interpreted by Wolfram Alpha to be what you want.

7

So, I thank everyone who replied. I’ve read more on this subject than i’d care to admit. I came across a blog by a Physicist who had also noticed the same thing. He asked Chatgpt why, and this is what Chatgpt said…

":four: Why numeric and symbolic differ

Numeric input: WA uses a calculator-style left-to-right evaluation: 6 ÷ 2 × 3 = 9

Symbolic input: WA uses algebraic conventions: a ÷ bc = a ÷ (b*c) = 1

So the difference comes from “numeric calculator rules vs algebraic coefficient rules.”

This seems to be what i was wanting to know.
Thanks.