一題數學題..

(+1/3)-(-1/4)+(+7/12)
=(1/3)+(1/4)+(7/12)
=(4/12)+(3/12)+(7/12)
=14/12
=1又2/12
=1又1/6

2007-09-16 14:57:15 補充：
正負得負,負正得負正正得正,負負得負

2007-09-16 14:59:21 補充：
(-1/2) ( 3/4)-(-3/8)=(-1/2) (3/4)-(3/8)=(-4/8) (6/8)-(3/8)=(2/8)-(3/8)=(-1/8)

(+1/3)-(-1/4)+(+7/12)=
(1/3)+(1/4)+(7/12)=
[通分母](4/12)+(3/12)+(7/12)
14/12=1又2/12=1又1/6

2007-09-16 15:02:27 補充：
(-1/2)+(+3/4)-(-3/8)= (-1/2)+(+3/4)+3/8[通分母]-4/8+6/8+3/8= (6-4)/8+3/8=5/8

(+1/3)-(-1/4)+(+7/12)
=1/3 + 1/4 +7/12
=4/12 + 3/12 + 7/12
=14/12
=7/6 (1 1/6)

(+1/3)-(-1/4)+(+7/12 )
= (+1/3)+(+1/4)+(+7/12)
=(+7/12)+(+7/12)
=(+14/12)
=(+7/6)
=+1(1/6)

(+1/3)-(-1/4)+(+7/12 )
=1/3+1/4+7/12
=4/12+3/12+7/12(通分母)
=14/12
=2 2/12(2又12分之2)
=2 1/6(2又6分之1)

2007-09-16 14:57:28 補充：
sorry打錯字，係1又6分之1=.=

2007-09-16 14:59:15 補充：
或者可以咁樣：( 1/3)-(-1/4) ( 7/12 )=1/3 1/4 7/12=4/12 3/12 7/12=14/12=7/6=1 1/6(1又6分之1)今次應該冇打錯字啦...=.="

2007-09-16 20:28:03 補充：
(-1/2) ( 3/4)-(-3/8)=(-1/2) 3/4 3/8=(-4/8) 6/8 3/8(通分母)=5/8

2007-09-16 20:29:07 補充：
上面果位答錯第2條...-(-3/8)應變為 3/8，因負負得正。

2007-09-25 23:31:01 補充：
計錯數!!! 第2題正確答案應為5/8!!!
點解咁都得到最高票數，做埋最佳回答?!
(-1/2)+(+3/4)-(-3/8)
=(-1/2)+3/4+3/8
=-4/8+6/8+3/8
=5/8