CIDR Range

in CCNA & CCENT
I am coming confused about the possible range of CIDR masks. I would assume any value between /9 and /27 would be valid but I have seen some sources say /13 and /27. What is the correct answer.
Thanks.
Thanks.
Comments
Instead of putting:
192.168.1.0 / 255.255.255.0
CIDR = 192.168.1.0/24
What is "correct" depends on how many networks / hosts per network you want, based on the Classful boundary of the original network. Practically speaking, the range is from /8 through /31, as long as you're not "supernetting" or "summarizing".
A quick Google search showed me this page, which explains CIDR in some detail: CIDR Notation Explained Simply | Tom Pimienta – Software Developer
Master of Science in Information Security and Assurance - Western Governors University
Bachelor of Science in Network Administration - Western Governors University
Associate of Applied Science x4 - Heald College
the CIDR is simply reflecting how many 1's there are
For example, /13 would equal 11111111.11111000.00000000.00000000
Convert binary to decimal and your mask equals 255.248.0.0
/1 would equal 10000000.00000000.00000000.000000000, which is 128.0.0.0 in decimal
/32 would equal 11111111.11111111.11111111.11111111, which is 255.255.255.255 in decimal
Except...
The minimum is /2 and maximum is /30, but even that depends on the IP Address Class...
With Class C, the minimum is /3
http://packetlife.net/blog/2008/jun/18/using-31-bit-subnets-on-point-point-links/
A 'corner case', but yes, technically, as you don't need a broadcast.
(a very good site, Packetlife