question: How many touchdowns were scored between 10 and 20 yards, inclusively?
#1 return touchdowns 
#2 return yards of #1 
#3 return #1 where #2 is at least 10 
#4 return #1 where #2 is at most 20 
#5 return #1 in  both #3 and  #4 
#6 return number of  #5