How do I write IPv4 slash notation in IPV6
The /24 in IPv4 is for small network. You can translate it in /96 for IPv6.

Here's the quote from documentation : 


  An IPv6 address range might look like ::1/128 for a single host (in
  this case the IPv6 loopback address) or fe80::7a31:c1ff:0000:0000/96
  for a small network.