有向數(10)

一定記下下列公式:
正正得正
負負得正
正負得負
負正得負
:):):):):):):):):):):):):):):):):):):):):):):):):):):)
(-5)(-9)(+6)=?
1.(-5)(-9)(+6)
=(-5)*(-9)*(+6)(括號和括號之間有*,是隱形的)
=5*9(負負得正)*6,(一定要拆括號)
=270
:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(:(
2.我想你是中一學生吧!
有括號的比喻:(-5y),(-123z),(+321)是因式分解用的
沒有括號的比喻:-5,123a,-21d是展開的結果
兩者最大的分別,是括號......
沒有括號的式,比喻:-3+5 (可以直接計算)=2
有括號的式,比喻:(-3)+5 (不可以直接計算)
=+(-3)+5
= -3(正負得負)+5
= 2
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☆End☆

注︰(x)(y)=xy=x乘y
括既意思係,o係括入面既野係完整一舊
eg:
5-(2+3)
=5-2-3
=0
--得正,-+得負,++得正
eg:
1-6
=1+(-1)(+6)<<<<<<<-+得負
eg:
(-5)(-9)(+6)
=(-5)(-9)(6)
=(-1)(-1)(5)(9)(6)
=(5)(9)(6)
=270

2007-08-24 14:51:50 補充：
括姐係符號同符號之間既分隔