Hole in a prism

This task is about calculating volumes of composite shapes.
a)  Show how to work out the volume of this wooden prism before a cylindrical hole is bored through it. 
 
 
 
 
 
 
 

Volume of wood in whole prism__________ cm3


b)  Show how to work out the volume of wood remaining in the prism after a cylindrical hole has been bored through it.
 
 
 
 
 
 
 

Volume of wood left __________ cm3