How do I figure out the subnet?

Applications IP Networking
1

Hi,
How do I get subnet from this:

10.252.0.138/25

Tnx

2 
IP        10.252.0.138    = 00001010 11111100 00000000 10001010
Netmask   255.255.255.128 = 11111111 11111111 11111111 10000000 (/25)
Network   10.252.0.128    = 00001010 11111100 00000000 10000000 (IP & Netmask)
Host      0.0.0.10        = 00000000 00000000 00000000 00001010 (IP - Network)
Broadcast 10.252.0.255    = 00001010 11111100 00000000 11111111 (IP | ^Netmask)
3

tnx Pludi