Math/Science question?

Question

I'm really confused about significant digits. Are these three answers right or wrong? Can someone please explain them to me?

1.50 grams has 3 sg

105.75 has 5 sg

213.80 has 5 sg

Answer 1

1.50g has three sinicant figures

105.7g has 5 significant figures

213.80g has 4 significant figures

signinficant figures tell the main numbers in a  set of numbers

like 1.6 has 2

1.60 still has 2

but

1.06 has 3

get it??

Answer 2

all three are right. you  will get a 100! :D

Answer 3

Your answers are correct. Good job! All numbers are significant, except for zero on occasions. When there is a zero at the end of a number and after a decimal point, it is significant because it became a zero when a number less than 5 was rounded down in the next place value. However, if it is before the decimal, but there are no numbers after it, it is not significant (ex. 1000 has 1 significant number, but 1000.0 has 5 and 1001 has 4). There are more rules, but I'm sure you've had to write them down. The rules for exceptions are pure memorization.

Here are some more examples:

3.14 - 3 significant digits

0.000198 - 3 sd

2.03076 - 6 sd

8.010 - 4 sd

Answer 4

yes they r right. the way i remember it is a little poem my teacher came up eit. " dot right, not left." if there is a dot you start from the right and the first non 0 number you count and every thing wit it. if there is no dot you start from the left and do the same after that.

hope this helps