$ perl -MDevel::Peek -E 'Dump 4 ** 0.5'
SV = NV(0xe245f0) at 0xe07860
  REFCNT = 1
  FLAGS = (PADTMP,NOK,READONLY,pNOK)
  NV = 2
$ perl -MDevel::Peek -E 'Dump sqrt(4)'
SV = NV(0x1e545f0) at 0x1e37860
  REFCNT = 1
  FLAGS = (PADTMP,NOK,READONLY,pNOK)
  NV = 2