Does "slash notation" differ between IPv6 and IPv4?

Yes. Slash notation for IPv4 and IPv6 is based on the same principle but the amount of addresses that each slash represents differs between the two protocols. It is difficult to make direct comparisons between IPv4 and IPv6 because of the very large numbers involved in IPv6 addressing. However, the example below gives a simple overview:

In IPv4 addressing, a /32 is equivalent to one single IP address.

In IPv6 addressing, a /32 results in 65,536 subnets, each of which is the size of a /48. Each /48 contains 65,536 /64s and each /64 contains 264 addresses. This means that each IPv6 /32 allocation contains 4.29 billion /64s (4.29 billion x (264 ) IPv6 addresses, which results in a number too large to be meaningful in print).

A /64 subnet is the smallest IPv6 assignment that an End User can receive according to the current IPv6 assignment policy. So, an End User assigned the smallest IPv6 assignment will receive 264 IPv6 addresses.

An End User assigned the smallest IPv4 assignment will receive one single IPv4 address.

CIDR Chart - IPv6

 

CIDR Chart - IPv4