Significant digits Definition and 52 Threads

hi guys... i'm taking an online course and i believe my work was marked wrong... State the number of significant digits. a) 0.0029550 m b) 7.050800 kN can someone please tell me the # of signifcant digits! is a) 4 or 5 and b) 5 or7 thanks guys...

Please, if someone helps, I will forever be in your debt! Just Gen Chem I...but its about Sig Figs...know one seems to know the rules about which law to use when you have mixed equations 0.0001235 X 0.0012 + ( 5.48 - 0.004) X 9.1 + (8.2 x10 raised to the neg 6) Give the correct answer...