Step 1 :\(0.285 \frac{1}{2} \% = 0.2855 \%\)
Step 2 :\(0.2855 \% = 0.2855 \div 100\)
Step 3 :\(0.2855 \div 100 = 0.002855\)
Step 4 :\(\boxed{0.002855}\)