Always convert the answers back into proper scientific notation form. Numbers written in scientific notation are assumed to be measurements, thus approximations. Therefore, the rules outlined below must be applied. Every nonzero digit in a recorded measurement is significant. 24.7 m, 0.743 m and 714 m all have three significant figures.
Zeroes appearing between nonzero digits are significant.
The measurements 7003 m, 40.79 m, and 1.503 m all have four significant figures. 0.0000099 only has two significant figures. Zeroes at the end of the number and to the right of the decimal are significant. The measurements 1241.20 m, 210.100 m and 5600.00 all have six significant digits. Zeroes at the end of a measurement and to the left of the decimal are ambiguous.