@ @¶ìÿa@óÝy‹¾a@ u@ @QT : () 11 () 13.21 +16.82 30.03 : 5.7 −3.2 2.5 () .1096 137 8 . .13.7 × 0.8 = 10.96 500 × (0.4)2 = 500 × 0.4 × 0.4 = 500 × 0.16 = 80.00 ( ) [Algebraic Expresions] (.) x. Ay .A = xy A = x × y .