Sig Figs

[ASetlur_1G]

Just to clarify...

400 is different from 400. in terms of sig figs right?
I'm under the impression that 400 is 1 sig fig and 400. is 3 sig figs because there is a decimal point after the 0.

Is this correct?

[rachelle1K]

Yes that is correct! A decimal implies that the zeros before it are significant.

[William Francis 2E]

Yes! You are correct. Furthermore, scientific notation could potentially be used to make it more clear that you answer is written with a certain number of sig figs. For instance, 400 could be written as 4.00 x 10^2. This may be preferable to writing "400." in some cases since the decimal may be easily missed by someone looking over your work.

[Keerthana Sivathasan 2E]

For better reference, here are some more rules:
1. Non zero digits are always significant.
2. Zeros between 2 significant digits are significant.
3. Trailing zeros and final zero are only significant in the decimal part.
4. For numbers less than 1 like in 0.05, the 0 before the decimal point is significant but the one after is not, because they are just place holders.
5. For whole numbers, leading and trailing zeros are not significant.