Comment on SBA #119 maths
mic_check_one_two@lemmy.dbzer0.com 2 weeks agoThis is actually a generational thing. Millennials were taught “PEMDAS”:
- Parenthesis
- Exponent
- Multiplication
- Division
- Addition
- Subtraction
But younger generations have been taught “BEDMAS” instead:
- Brackets
- Exponent
- Division
- Multiplication
- Addition
- Subtraction
Notably, Division and Multiplication are swapped on PEMDAS and BEDMAS, to make this “both happen at the same time” more straightforward. But that only applies if the entire operation can happen at the same time.
For instance, let’s say 6/2(3) compared to 6÷2(3). At first glance, they both appear to be the same operation. But in the former, the 6 dividend would be over the entire 2(3) divisor. Which means you would need to simplify the divisor (by resolving the multiplication of 2•3) before you divide. So the former would simplify to 6/6=1, while the latter would divide first and become 3(3)=9.
Technically, if you wanted to be completely clear, you would write it using multiple parenthesis as needed. For instance, you would write it as either:
(6÷2)(3)=9 or 6÷(2(3))=1 to avoid the ambiguity. Then it wouldn’t matter if you’re using PEMDAS or BEDMAS.
AHemlocksLie@lemmy.zip 2 weeks ago
I have never heard of or seen an example of anyone using / and ÷ in different ways. If you want multiple terms in your divisor, either write it as a large fraction with all relevant terms in the dividend or divisor, or use parentheses. This just seems like sloppy notation to me.
mic_check_one_two@lemmy.dbzer0.com 2 weeks ago
It was just because MarkDown doesn’t really make mathematical notation easy. The point is that with a slash, the 6 is over the entire
2(3)divisor. It’s the difference between these:Image
You can even see that the automatic solution (in yellow) parses the two differently. In the first example, it correctly resolves the
2(3)first. But in the second, it parses the6÷2first, because it is left ambiguous.