A miligram (mg) is equivalent to
On the other hand, 1 kg is equivalent to
![1\operatorname{kg}=1000g=10^3g]()
Then, a kilogram is also equal to:
![\begin{gathered} 1\operatorname{kg}=10^3g=10^3(1g)=10^3(10^3mg)=10^6mg=1000000mg \\ \Rightarrow1\operatorname{kg}=1000000mg \\ \Rightarrow3.6\operatorname{kg}=3600000mg=3.6\cdot10^6mg \end{gathered}]()
The answer is then 3.6kg=3.6*10^6mg=3600000mg
The last line is the answer to question 3 in expanded form and in scientific notation.
As for question 4.
![\begin{gathered} 1nm=10^(-9)m\Rightarrow1m=10^9nm \\ 1\operatorname{km}=10^3m \\ \Rightarrow1\operatorname{kg}=10^3(10^9nm)=10^(12)nm \\ \end{gathered}]()
Finally, we need to multiply both sides of the equation by 0.004=4*10^-3
![\begin{gathered} \Rightarrow0.004\operatorname{kg}=0.004(10^(12)nm) \\ \Rightarrow4\cdot10^(-3)\operatorname{kg}=4\cdot10^(-3)\cdot10^(12)nm=4\cdot10^9nm=4000000000nm \end{gathered}]()
Then, the answer is 0.004km=4*10^-3km=4*10^9nm=4000000000nm