數學計算過程不會～急

1.
(5/6) - (3/8) + (-2又7/8)
=(5/6) - (3/8) - (2又7/8)
=(5/6) - (3/8) - (23/8)
= (20/24) - (9/24) - (69/24)
= (20 - 9 - 69)/24
= -58/24
= -29/12
= -2又5/12


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2.
[3 + (3/5)] - [4 - (1/4)] + [8 - (3/8)]
= (18/5) - (15/4) + (61/8)
= (144/40) - (150/40) + (305/40)
= (144 - 150 + 305)/40
= 299/40
= 7又19/40


====
3.
(-2又2/5) + (-7/4) - (-5又1/3)
= -(12/5) - (7/4) + (16/3)
= -(144/60) - (105/60) + (320/60)
= (-144 - 105 + 320)/60
= 71/60
= 1又11/60


====
4.
(2/3) - (15又1/4) - [(4又1/2) - (3又5/6)]
= (2/3) - (15又1/4) - (4又1/2) + (3又5/6)
= (2/3) - (61/4) - (9/2) + (23/6)
= (16/24) - (366/24) - (108/24) + (92/24)
= (16 - 366 - 108 + 92)/24
= -366/24
= -61/4
= -15又1/4


====
5.
(1又2/3) - [(6/7) - (1又1/3)]
= (5/3) - (6/7) + (4/3)
= (35/21) - (18/21) + (28/21)
= (35 - 18 + 28)/21
= 45/21
= 15/7
= 2又1/7


====
6.
(2/3) - 4 + [(1又3/4) - (5/2)] + (1/12)
= (2/3) - 4 + (1又3/4) - (5/2) + (1/12)
= (2/3) - 4 + (7/4) - (5/2) + (1/12)
= (8/12) - (48/12) + (21/12) - (30/12) + (1/12)
= (8 - 48 + 21 - 30 + 1)/12
= -48/12
= -4


====
7.
[(-8又1/2) + (5/13)] + (-1又1/2)
= -(8又1/2) + (5/13) - (1又1/2)
= -(17/2) + (5/13) - (3/2)
= -(221/26) + (10/26) - (39/26)
= (-221 + 10 - 39)/26
= -250/26
= -125/13
= -9又8/13


====
8.
[(-103/111) + (3/17)] + (-8/111)
= -(103/111) + (3/17) - (8/111)
= [(-103/111) - (8/111)] + (3/17)
= [(-103 - 8)/111)] + (3/17)
= -(111/111) + (3/17)
= -1 + (3/17)
= -(17/17) + (3/17)
= (-17 + 3)/17
= -14/17


====
9.
(19/13) + [(-1/7) - (6/13)]
= (19/13) - (1/7) - (6/13)
= [(19/13) - (6/13)] - (1/7)
= [(19 - 6)/13] - (1/7)
= 1 - (1/7)
= (7/7) - (1/7)
= (7 - 1)/7
= 6/7

2013-11-19 01:22:15 補充：
在發問時已扣除點數，刪除問題只會損人不利己。