(iWork) Numbers: Cut and Paste, macros
One way to cut formula and paste in new location with references 'in tact and relative' is following:

navigate to desired cell containing formula
⌥ + ⏎ ('enter cell edit mode', same as F2 in Windows Excel)
⌘ + A ('select all')
⌘ + X ('cut')
⏎ ('exit cell')
navigate to destination cell
= (opens popup window for entering formula)
⌘ + V ('paste')

Alternatively one can make references in formula absolute with ⌘ + K and then cut-paste whole cell.