假設原本有$10, 用$8買雞, 剩$20 P! K v7 b6 r3 r4 x/ l
之後$9賣出, $2+$9 = $11
9 X$ X: z1 b" a7 Z5 e* Y( N4 d5.39.217.77再用$10買雞, $11-$10 = $15.39.217.77& u$ e8 T9 D: I8 ]# ?. o* ]
又再以$11賣出, $1+$11 = $12tvb now,tvbnow,bttvb# G! W% u# l9 A$ V* u9 P5 ?7 p7 f; A
$12-$10 = 賺$2 |