How do I denote only some zeros as significant

Question

I want to write 45,000 with some numbers of significant figures.

It's really easy to write it with 2 significant figures: 45,000

5 significant figures is also easy: 45,000.

6 and up is also easy: 45,000.0

But how do I write it with 3 or 4 significant figures? I know it can be done with scientific notation, but I want to see if there's a way without it, since scientific notation can sometimes make the size of a number less visually obvious. Is this just a lexical gap with the notation, or is there a way to do it?

Answer 1

use scientific notation:

2 significant digits can be represented by: $4.5 $x$(10^4)$

3 significant figures can be represented by: $4.50 $x$(10^4)$

4 significant figures can be represented by: $4.500 $x$(10^4)$

Answer 2

I was taught that you could show that with an underline, so $45,0\underline00$ would have four significant figures. I have never seen it since, so I wouldn't expect people to understand it.

Answer 3

If the number has a unit U, you can abbreviate the unit and add decimals as appropriate:

2 significant figures: $45$ kU

3 significant figures: $45.0$ kU

4 significant figures: $45.00$ kU