subnetting ccna help

[~Stevief~]

I've got my semester 1 exam coming up after christmas, any ccna people help this sink in as my brain is turning to mush

132 64 32 16 8 4 2 1

working from the left side is subnets,right side hosts i think

so if i needed a network of 25 users i would count from right side 2/4/8/16/32, so my address table will go up in 32's

ie 0 (in here would be usable addresses) 31
32 63
64 127
128 255
256

am i on the right track as i'm not sure thats right

Also what does the /26 mean??

 

[~Stevief~]

LOL, Thanks for the reply, it made a lot of sense. Serves me right for cheating and using subnet calcs while practicing

ps, I've been working up north and had no time to reply...sorry but very grateful for the reply