Exponential Expression - возведение в степень.

irb(main):001:0> print "In IPv4, there are #{2**32} addresses"

In IPv4, there are 4294967296 addresses

irb(main):001:0> print "In IPv6, there are #{2**128} addresses"

In IPv6, there are 340282366920938463463374607431768211456 addresses

Собсна, сабж :)