3100.0 x 10^2 how many signifigaint digits are in this

3100.0 x 10^2 how many signifigaint digits are in this 

=310,000 All six digits are significant.

3100.0 x 10^2 how many signifigaint digits are in this 

I think 5 are significant.  

What do you think Rom ?

The 3 and the 1 are the significant digits here so just 2.

Thanks Rom, you are probably right but

I thought that in chemistry it was taught that if a zeros were put after the point it implied that all the digits up to that one were significant.  Hence 5

If it had been written as 3100* 10^2   I would have said with confidence that there were only 2 significant figures.  ://

Actually Melody you are correct.  I'm mistaken.

From Wiki

"In a number with a decimal point, trailing zeros, those to the right of the first non-zero digit, are significant."

so 5 is the correct answer.