okay so I've been on this problem for 30 minutes: [ ( 2.99*10^6 ) / 44.892 ] +146.04 using sig figs... I just can't understand it! :(
+118653 $$\left({\frac{\left({\mathtt{2.99}}{\mathtt{\,\times\,}}{{\mathtt{10}}}^{{\mathtt{6}}}\right)}{{\mathtt{44.892}}}}\right){\mathtt{\,\small\textbf+\,}}{\mathtt{146.04}} = {\mathtt{66\,750.334\: \!751\: \!848\: \!881\: \!760\: \!7}}$$
Well the first three digits are 667 (the next one 5 is used for rounding if it is 5 or bigger the the third one goes up) so now we have
668 but 668 is much smaller than 66 750 we can't have that. We need some zeros but they are not significant.
So the answer is
66,800
+118653 Hlow many significant figures? - Are you supposed to be estimating it or doing it on a calculator?
$$\left({\frac{\left({\mathtt{2.99}}{\mathtt{\,\times\,}}{{\mathtt{10}}}^{{\mathtt{6}}}\right)}{{\mathtt{44.892}}}}\right){\mathtt{\,\small\textbf+\,}}{\mathtt{146.04}} = {\mathtt{66\,750.334\: \!751\: \!848\: \!881\: \!760\: \!7}}$$
+118653 $$\left({\frac{\left({\mathtt{2.99}}{\mathtt{\,\times\,}}{{\mathtt{10}}}^{{\mathtt{6}}}\right)}{{\mathtt{44.892}}}}\right){\mathtt{\,\small\textbf+\,}}{\mathtt{146.04}} = {\mathtt{66\,750.334\: \!751\: \!848\: \!881\: \!760\: \!7}}$$
Well the first three digits are 667 (the next one 5 is used for rounding if it is 5 or bigger the the third one goes up) so now we have
668 but 668 is much smaller than 66 750 we can't have that. We need some zeros but they are not significant.
So the answer is
66,800
+8262 Melody, I see that the posts you make are always interesting. Can you please teach me more LaTex please?
+118653 None of this is in LaTex Dragon.
You are best to go to the LaTex thread and see if there is something in there that you would like to copy.
We all learn LaTex by copying others.
I am quite impressed with what you have already learned but it would be good if you learn more. 
