a. maths

-1-1
=(-1)+(-1)
=-2
兩個-1加起來就等於-2
+1+1
=(+1)+(+1)
=+2
wish you can understand!!!!!!!!!

2007-10-15 16:51:55 補充：
補充:假設你有10元, 買鉛筆和鉛子筆各一支, 他們每支的價錢都是1元, 還剩下多少元? 10-1-1=8元 10-(1+1)=10-2=8元所以-1-1=-(1+1)=-2(需付2元)

-1-1=?
so easy!!!!!!!!!!
答案no1
it should-1-1=-2
do you know???????

你可以make條number line


-3 -2 -1 0 +1 +2 +3

減=向左 加=向右

咁-1 向左行一格(because -1-1)answer就係-2喇......


so.........-1-1= -2

hope can help u....

如果你係 -1乘-1 當然等於1 了，負負得正, 1x1=1
所以(-1)x(-1) =1

-1-1=-2