$a)1m=1000mm={10}^{3}mm$   

$1mm=\frac{1}{1000}m=\frac{1}{{10}^3}m={10}^{-3}m$  

$465m=4,65\cdot {10}^{2}m=4,65\cdot {10}^2\cdot {10}^{3}mm=4,65\cdot {10}^{5}mm$  

$465mm=4,65\cdot {10}^{2}mm=4,65\cdot {10}^2\cdot {10}^{-3}m=4,65\cdot {10}^{-1}m$  
$\underline{\underline{}}$  

$b)1km=100000cm={10}^{5}cm$  

$1cm=\frac{1}{100000}km=\frac{1}{{10}^5}km={10}^{-5}km$  

$40000\text{km}=4\cdot {10}^4\text{km}=4\cdot {10}^4\cdot {10}^5\text{cm}=4\cdot {10}^9\text{cm}$  

$40000\text{cm}=4\cdot {10}^4\text{cm}=4\cdot {10}^4\cdot {10}^{-5}\text{km}=4\cdot {10}^{-1}\text{km}$  
$\underline{\underline{}}$  

$c)1\text{kg}=1000\text{g}={10}^3\text{g}$  

$1\text{g}=\frac{1}{1000}\text{kg}=\frac{1}{{10}^3}\text{kg}={10}^{-3}\text{kg}$  

$326\text{kg}=3,26\cdot {10}^2\text{kg}=3,26\cdot {10}^2\cdot {10}^3\text{g}=3,26\cdot {10}^5\text{g}$  

$326\text{g}=3,26\cdot {10}^2\text{g}=3,26\cdot {10}^2\cdot {10}^{-3}\text{kg}=3,26\cdot {10}^{-1}\text{kg}$  
$\underline{\underline{}}$  

$d)1\text{t}=1000000\text{g}={10}^6\text{g}$  

$1\text{g}=\frac{1}{1000000}\text{kg}=\frac{1}{{10}^6}\text{kg}={10}^{-6}\text{kg}$  

$550\text{t}=5,5\cdot {10}^2\text{t}=5,5\cdot {10}^2\cdot {10}^6\text{g}=5,5\cdot {10}^8\text{g}$  

$550\text{g}=5,5\cdot {10}^2\text{g}=5,5\cdot {10}^2\cdot {10}^{-6}\text{t}=5,5\cdot {10}^{-4}\text{t}$