#### Answer

a) 0.0321
b) 0.000508
c) 0.001219
d) 0.162

#### Work Step by Step

a) $3.21\times10^{-2}$
Replace the comma two places to the left, so the decimal notation is 0.0321
b) $5.08\times10^{-4}$
Replace the comma four places to the left, so the decimal notation is 0.000508
c) $121.9\times10^{-5}$
Replace the comma five places to the left, so the decimal notation is 0.001219
d) $16.2\times10^{-2}$
Replace the comma two places to the left, so the decimal notation is 0.162