Significant digits

significant digits any digit from 1-9 is significant trailing zeros are significant eg 6.3800,12000 ''sandwich'' zeros are significant eg 2.04,1005.002 leading zeros are not significant eg 0.0065 counted objects and constants are not included in sig digs X/%: multiply or divide then round answer to the lowest number of sig digs +/-: add or subtract then round answer to the lowest number of decimal places EX) 2.0X20.00 = 40 EX) 5.2+2.35 =7.55 which will be 7.6 scientific notation EX) 5⁶55.(2SD) = 5.7X10³ 5100 SI prefixes EX) 2000mL = 2.000L unit analysis EX) 10 mol X 2 mol/L = 20L = 2X/0¹L