finite-digit arithmetic and significant digits

[PG1995]

Hi

Could you please help me with **broken link removed** queries? Thanks a lot.

Regards
PG

 

[KeepItSimpleStupid]

PG:

Your reading more into it. I know you want to replace "three digit arithmetic" with 3 significant figures. Don't. That's not what's asked.

You cannot do the problem with 1234.5678 with 3 digit math.

I don't like the term (chopping). Truncated or truncation is the proper term.

Three significant figures is a different problem.

I think it's an example that's poorly done and leads to confusion, but 1234.5678 to 3 significant digits is 1.23E1

This is "What does teach want"? Anyway you look at it, when I count 1234 is 4 digits and so is 1230. 123e1 is 3 significant digits and so CAN 1230 be 3 significant digits, but only 123e1 makes it CLEAR that it's 3 significant digits.

 

[jpanhalt]

I was taught the rules described in Wikipedia (See: significant digits).

Source: https://en.wikipedia.org/wiki/Significant_figures
The significance of trailing zeros in a number not containing a decimal point can be ambiguous. For example, it may not always be clear if a number like 1300 is precise to the nearest unit (and just happens coincidentally to be an exact multiple of a hundred) or if it is only shown to the nearest hundred due to rounding or uncertainty. Various conventions exist to address this issue:<snip>

As for determining what the teacher wants, I couldn't agree more. You have to learn the rules, even if they are not rigorously applied in life. Also, the rules don't include consideration of context, which can and usually does affect the interpretation of precision/significant figures.

John

Edit: I misread KISS's example of how to handle a trailing zero.

 

[KeepItSimpleStupid]

And 1230 can be 3 or 4 significant figures. Depends on context. 1230e0 is definitely 4 sig figs.