question: How many more elephants lived in Central Africa in 1989 compared to East Africa?
#1 return Central Africa 
#2 return East Africa 
#3 return elephants in  1989 of #1 
#4 return elephants in  1989 of #2 
#5 return number of  #3 
#6 return number of  #4 
#7 return the  difference of #5 and  #6