question: How many million people in the immigrant population are not between the ages of 18 and 50?
#1 return immigrants 
#2 return #1 that are between the  ages of 18 and  50 
#3 return population in  millions of people of  #1 
#4 return population in  millions of people of  #2 
#5 return the  difference of #3 and  #4