cross multiplication

20 LETTERS · STARTS WITH C

cross multiplication is a valid 20-letter word worth 27 points in Scrabble and 35 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

C3R1O1S1S1M3U1L1T1I1P3L1I1C3A1T1I1O1N1

3 + 1 + 1 + 1 + 1 + 0 + 3 + 1 + 1 + 1 + 1 + 3 + 1 + 1 + 3 + 1 + 1 + 1 + 1 + 1 =27 PTS

DOUBLE WORD → 54TRIPLE WORD → 81

MEANING

What does cross multiplication mean?