## How many sig figs when in decimals?

Bryce Ramirez 1J
Posts: 120
Joined: Sat Aug 24, 2019 12:16 am

### How many sig figs when in decimals?

How many sig figs are there for 0.0001? Because 1 is the last number and includes all the zeros, I thought it would be four, but it says that the amount is 1? What is the rule for zeros in this case?

SVajragiri_1C
Posts: 115
Joined: Thu Jul 11, 2019 12:16 am

### Re: How many sig figs when in decimals?

In a decimal, you start counting sig figs at the first non-zero digit, whether it be before or after the decimal point.
So for example,
0.00345 has 3 sig figs.
3.034 has 4 sig figs.
0.0200 has 3 sig figs.

Tooba_1A
Posts: 11
Joined: Wed Sep 11, 2019 12:16 am

### Re: How many sig figs when in decimals?

There would only be one sig figs, considering that the only significant number (1), only appears after 4 other zeroes, all of which aren't considered significant. Some factors that could have changed this outcome is there being another number before the zeroes, deeming all the zeroes after a significant and making it 5 significant figures. Additionally, if there had been zeroes after the 4, those would have been counted as well since they had occurred after an important number.

Tooba_1A
Posts: 11
Joined: Wed Sep 11, 2019 12:16 am

### Re: How many sig figs when in decimals?

There would only be one sig figs, considering that the only significant number (1), only appears after 4 other zeroes, all of which aren't considered significant. Some factors that could have changed this outcome is there being another number before the zeroes, deeming all the zeroes after a significant and making it 5 significant figures. Additionally, if there had been zeroes after the 4, those would have been counted as well since they had occurred after an important number.

Pipiena Malafu 3J
Posts: 39
Joined: Fri Sep 28, 2018 12:27 am

### Re: How many sig figs when in decimals?

Long story short, leading zeroes (or zeroes before numbers other than zero) are never significant and thus there is only one significant figure for numbers like "0.002" and such.

J Medina 2I
Posts: 102
Joined: Wed Sep 25, 2019 12:17 am

### Re: Significant Figures if last digit is 5

I was reading through the link "EVERYTHING YOU WANTED TO KNOW ABOUT SF" posted on the class website to review significant figures and was confused when I read that if a number ends in the number '5' and you are rounding, that you must round the number up or down to the nearest even number. I always thought a number ending in '5' always meant to round up. In the example given 2.65 turns into 2.6 when rounded. Is anyone else unfamiliar with this rule?

205154661_Dis2J
Posts: 109
Joined: Wed Sep 18, 2019 12:21 am

### Re: How many sig figs when in decimals?

I attended Step-Up session today and we went over sig figs. The UA told us to remember this:
1) Non-zero digits are always significant.
2) Any zero between two digits are significant.
3) Final zero or trailing zero in decimal portion ONLY are significant.
Hope this helps!