Given IP  3 . 60 . 43 . 186 / 12  
#1. & 2.  Find the SubNetwork 

#3.  Find the First useable IP address  3 . 48 . 0 . 1 
#4.  Find the Broadcast address  3 . 63 . 255 . 255 
#5  Find the Last useable IP address  3 . 63 . 255 . 254 
#6.  What is the Total Number of IPs per Subnet?  1048576 
#7.  How many useable Hosts address per subnet?  1048574 
#8.  What is the Next Subnet Number?  3 . 64 . 0 . 0 
#9.  What IP Class is this?  Class A 
#10.  How many possible Subnetworks with this class?  Bits this Class = 8 Bits Subnet Mask= 12 2^ 4 = 16 