Significant Figures vs Decimal Places

[a weaponized ikea chair]

Is there a difference?

Like what is 0.00678143 to three decimal places, compared to three significant figures? I've always used them interchangeably.

[Evolio]

Yes, there is a difference.

It would be 0.007 to 3 decimal places.

It would be 0.00678 to 3 significant figures according to VCAA's guidelines:
- Following zeros (after non-zero numbers) are always significant
- Leading zeros (before non-zero numbers) are never significant
- Zeros in between non-zero numbers count as a sig fig
- All numbers except 0 count as a sig fig

Specifying sig figs are usually seen in Physics and Chemistry and not really Methods though. They usually ask you to express your answer to a specific number of decimal places in Methods.

[a weaponized ikea chair]

Yes, there is a difference.

It would be 0.007 to 3 decimal places.

It would be 0.00678 to 3 significant figures according to VCAA's guidelines:
- Following zeros (after non-zero numbers) are always significant
- Leading zeros (before non-zero numbers) are never significant
- Zeros in between non-zero numbers count as a sig fig
- All numbers except 0 count as a sig fig

Specifying sig figs are usually seen in Physics and Chemistry and not really Methods though. They usually ask you to express your answer to a specific number of decimal places in Methods.

Do you round significant figures?

[Evolio]

What do you mean?
For example, if it says 'write your answer to 2 sig figs', there should only be 2 sig figs in your answer.

[a weaponized ikea chair]

What do you mean?
For example, if it says 'write your answer to 2 sig figs', there should only be 2 sig figs in your answer.

lets say 0.00898999 to three sig figs. Would you out 0.00899, or 0.00898?

[Evolio]

Oh, I get what you mean now.
Yes, you do round. So, it would be 0.00899.