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JeffBeallFlag for United States of America

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subnetting

I'm studying for the Network + test, and for subnetting, I don't have a problem subnetting class C networks, but I'm confused on class B.
the method the book I'm using is to ask 5 questions
how many subnets - the formula is 2 to the X power - x = number of masked bits - no problems there
how many hosts per subnet - formula is 2 to the Y power minus 2    y = number of host per subnet
what art the valid subnets formula is  265 - subnet mask = block size aka increment number   -  now this is what throws me,
so, for example, if i have a class B network and the mask is 255.255.240.0 (/20) i would use the formula
256-240 = 16 so the block size or increment number is 16. in the book, he makes a chart like this

subnet        0.0         16.0              32.0          48.0
first host     0.1         16.1              32.1          48.1
last host     15.254   31.254         47.254      63.254
broadcast   15.255   31.255        47.255       63.255

so does this mean that in the first column for instance. if the address is 172.16.X.Y the first host address is 172.16.0.1 and the last address in subnet 0.0 is 172.16.15.254? which means there are LOTS of hosts?
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Ken Boone
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ok, thank you.