how to use 'Number' PMC?

[Vadim Konovalov]

Hi,

the 
http://docs.parrot.org/parrot/latest/html/docs/book/pir/ch04_variables.pod.html 
reads:

  $P0 = new 'Integer'
  $P0 = 5

  $P1 = new 'String'
  $P1 = "5 birds"

  $P2 = new 'Number'
  $P2 = 3.14

the first 2 are no problems, but I can't use the last, due to the following  
error:

Class 'Number' not found

TIA,
Vadim.