system of numeration

NOUN
20 LETTERS · STARTS WITH S

system of numeration is a valid 20-letter word worth 28 points in Scrabble and 32 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
S1Y4S1T1E1M3O1F4N1U1M3E1R1A1T1I1O1N1
1 + 4 + 1 + 1 + 1 + 3 + 0 + 1 + 4 + 0 + 1 + 1 + 3 + 1 + 1 + 1 + 1 + 1 + 1 + 1 =28 PTS
DOUBLE WORD → 56TRIPLE WORD → 84
MEANING

What does system of numeration mean?