A rational number is a number equal to a common fraction,
whether proper of improper.

a.  



This is complex because after simplifying it 
contains an "i".


b. 

This can be written as , and
we can multiply top and bottom by 100 and
get rid of the edcimal. So we have



which reduces to  which is a 
common fraction, so it is rational.

c. 

This is not equal to any common fraction, but
doesn't contain any  so it's irrational.

You should note here that  is NOT equal
to .  The RATIONAL NUMBER 
is only an approximation for .

d.  
   
   
   
   

Since  can be written as the common fraction
 it is rational.  
   
e. 
   

This cannot be simplified further, and it is not equal
to any common fraction, but doesn't contain any ,
so it's irrational.  

Edwin