Given IP  159 . 21 . 104 . 19 / 19  
#1. & 2.  Find the SubNetwork 

#3.  Find the First useable IP address  159 . 21 . 96 . 1 
#4.  Find the Broadcast address  159 . 21 . 127 . 255 
#5  Find the Last useable IP address  159 . 21 . 127 . 254 
#6.  What is the Total Number of IPs per Subnet?  8192 
#7.  How many useable Hosts address per subnet?  8190 
#8.  What is the Next Subnet Number?  159 . 21 . 128 . 0 
#9.  What IP Class is this?  Class B 
#10.  How many possible Subnetworks with this class?  Bits this Class = 16 Bits Subnet Mask= 19 2^ 3 = 8 