Răspuns :
9 x 3 - 9 x 2 = 27 - 18 = 9
sau:
( 9 x 3 ) - ( 9 x 2) = 27 - 18 = 9
sau :
( 9 + 9 +9 ) - ( 9 + 9 ) = 27 - 18 = 9
sau:
( 9 x 3 ) - ( 9 x 2) = 27 - 18 = 9
sau :
( 9 + 9 +9 ) - ( 9 + 9 ) = 27 - 18 = 9