+-------------------------+---------------------+----------+
|     Network Section     |     Host Section    | Net Mask |
+---+---------+-----------+---------+-----------+----------+
|128|1        |   0/510   | 000 0000| 126/32,766|1/9/17/25 |
|192|11       |   2/1,022 |  00 0000|  62/16,382|2/10/18/26|
|224|111      |   6/2,046 |   0 0000|  30/8,190 |3/11/19/27|
|240|1111     |  14/4,094 |     0000|  14/4,094 |4/12/20/28|
|248|1111 1   |  30/8,190 |      000|   6/2,046 |5/13/21/29|
|252|1111 11  |  62/16,382|       00|   2/1,022 |6/14/22/30|
|254|1111 111 | 126/32,766|        0|   0/510   |7/15/23/31|
|255|1111 1111| 254/65,534|         |   X/254   |8/16/24/32|
+---+---------+-----------+---------+-----------+----------+

Aint that hard, learn this.


example: 255.255.255.240 has a block size of 256-240, or 16. Meaning the first 
subnet after the zero subnet is 16, second subnet is 32, first subnets broadcast is 31, host ranges 17~30. That?s it, done, move on ;)

Good luck