Significant figures

[Ruby Sanchez 1K]

I had a question relating to what counts as a significant figure, I know that a number such as 400 only has one sig fig but would that change if the number had a decimal after it? Foe example if it was 400. or would that still be 1 sig fig?

[Kaya Lu 2K]

Yes, 400 is 1 significant figure, but with the addition of a decimal (400.), it becomes 3 significant figures. Hope this helps!

[RiaCasas2L]

Digits on the left of a decimal will always be significant, unless it's a zero such as 0.400 (three sig figs.). So for your example of 400., that would be three significant figures. However, if it was 400.0, that would be four significant figures because zeros after the decimal are significant as long as they don't come after a non-zero number.

[405957853 3I]

Well 400. isn't really a number but if you meant 400.0, then that would actually be 4 sig figs because the decimal ".0" indicates precision and therefore is significant.