incalculable (adj) – beyond calculation; unable to be predicted, determined, or reckoned; extremely numerous or great
BREAKDOWN: IN- (not) + CALC- (pebble used for counting) + -ABLE (able to be)
This word is built on the root CALC-, which means small stone, pebble used for counting, lime or calcium, or heel.
Common CALC- words include calcium, calculator, chalk, and miscalculate.
More esoteric CALC- words include calx, calcareous, and calculous.