唔識計數!!!20分

步驟如下

[(-5)(-2)-(+3)(+4)]/[(-6)+(-4)]x(+2)

= (10-12) / (-10)x(2)

= (-2) / (-20)

= 1/10

答案系十分之一

提一下：

1. 負數 x 負數 = 正數

2. 如果有個正數，例如： (+2）個“+”字唔洗寫出黎

希望幫到你～～ :D

2010-09-16 22:41:10 補充：
其實你可以用計數機check下：

先計[(-5)(-2)-(+3)(+4)]，(-5)(-2) = 10，(+3)(+4）=12，10 - 12 = -2， 呢個系個分子。

之後計[(-6)+(-4)]x(+2)， （-6）+（-4）即 （-6-4）= -10， （-10）x2 = -20 呢個系個分母。

最後計（-2）/（-20） = 1/10 = 0.1

2010-09-19 19:43:11 補充：
受教了～對網上的數學符號不太熟悉～

I think only 回答者Sky gets the right answer. The answer should be 0.4.

Consider two 大括號 first, [ ]/[ ]. Get the quotient, then multiplied by (+2). (+2) is not part of the denominator. If (+2) is, it should be inside another bracket { }, like { }/{[ ] x (+2)}.

[(-5)(-2)-(+3)(+4)]/[(-6)+(-4)]x(+2)]

= (10-12) / (-10)x(2)

=-2/-20

= 1/10

方法:

1.正數 x 正數 = 正數 eg. 1x1=1
2.負數 x 負數 = 正數 eg.(-1) x (-1) = 1
3.正數 x 負數 = 負數 eg. 1 x (-1) = -1
4.負數 x 正數 = 負數 eg. (-1) x 1 = -1

[(-5)(-2)-(+3)(+4)]/[(-6)+(-4)]x(+2)

=[-5-2-3+4]/[-6-4]x+2

=[-10+4]/-10x+2

=-6/-(10x2)

=-6/-20

=+(6/20)

=+3.33

i don't know is it right , i am just from 1 student , u can try ( 2 dp )

[(-5)(-2)-(+3)(+4)]/[(-6)+(-4)]x(+2) （計左大括號內的算先。再計其他）

=[(+10)-(+12)]/[(-6)+(-4)]x(+2)
=(-2)/[(-6)+(-4)]x(+2)
=(-2)/(-10)x(+2)
=+0.2x(+2)
=0.4

希望幫到你！

2010-09-18 00:25:26 補充：
係喔。計錯左......多謝提醒

(10-12)/(-10)x4
-2/-10*4
0.2*4
0.8