問問題!!

1.(a)
(-6)x(-3)+(-2)
=(-18)-2
=-20

(b)
(+3)+(-1)x(-3)
=3+3
=6

2.(a)
(-2)+(+5)(-3)-(-1)
=(-2)+(-15)+1
=-16

(b)
(+3)-(-2)+(+2)(-3)
=3+2+(-6)
=-5

3. (a)
(-3)(-2)+(-4)(-1)
=(-6)+(-4)
=-10

(b)
(+8)(+3)-(-7)(-4)
=24-28
=-4

2007-09-29 10:35:50 補充：
sorry, 1(a) 應該係(+18)(-6)x(-3) (-2)=18-2=16

2007-09-29 10:37:43 補充：
2 (b)(+3)-(-2)+(+2)(-3)=3+2+(-6)=-1 (不是-5, 打錯了)

2007-09-29 10:39:28 補充：
3. (a)(-3)(-2)+(-4)(-1)=6+4=10 (不是-10)

１ａ）＋１６
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唔知岩唔岩呢，我ｄ數學唔係幾好＞＜

有兩個原則...
1. 先乘除, 後加減
2. 乘除數時, 記住正正得正, 負負得正, 正負得負, 負正得負. (記著只局限乘除)

以1a為例...
(-6)x(-3) + (-2)

當然是計乘數先, 在(-6) x (-3)當中, 由於兩個數字都是負數, 所以負負得正, 最後答案必是正數.
(-6) x (-3) = +18
所以...
(-6)x(-3) + (-2)
=18 + (-2)
=18-2 (又是正負得負)
=16

之後自己試下計...不過我可以畀個answer你, 自己計完對答案
1b) 6
2a) -16
2b) -1
3a) 10
3b) -4

1a)
(-6)*(-3) + (-2)
= (+18) + (-2)
= (+18) - 2
= +16
b)
(+3) + (-1)*(-3)
= (+3) + (+3)
= (+3) + 3
= +6

2a)
(-2) + (+5)(-3) - (-1)
= (-2) + (-15) + 1
= (-2) - 15 + 1
= (-17) + 1
= -16
b)
(+3) - (-2) + (+2)(-3)
= (+3) - (-2) + (-6)
= (+3) + 2 - 6
= (+5) - 6
= -1

3a)
(-3)(-2) + (-4)(-1)
= (+6) + (+4)
= +10
b)
(+8)(+3) - (-7)(-4)
= (+24) - (+28)
= (+24) - 28
= -4