分數急急急急急急急急呀！！！（解答贈點15點）

2又1/2減1又3/4減?＝1/4

(2*2+1)/2 - (1*4+3)/4 - Y = 1/4
5/2 - 7/4 - Y = 1/4
Y = 1/4 - 5/2 + 7/4
Y = 1/4 - (2*5)/(2*2) + 7/4
Y = 1/4 - 10/4 + 7/4
Y = (1-10+7) / 4
Y = -2/4
Y = -1/2

2010-10-27 13:26:50 補充：
sorry..... 搞錯左d野.....

(2*2+1)/2 - (1*4+3)/4 - Y = 1/4
5/2 - 7/4 - Y = 1/4
Y = 5/2 - 7/4 - 1/4
Y = (5*2)/(2*2) - 7/4 - 1/4
Y = 10/4 - 7/4 - 1/4
Y = (10-7-1) / 4
Y = 2/4
Y = 1/2

2又1/2減1又3/4減?＝1/4
?是甚麼

2 1/2 - 3/4 - ? = 1/4
=2 2/4 - 3/4 - ? = 1/4
=1 6/4 - 3/4 - ? = 1/4
=1 3/4 - ? = 1/4
=1 3/4 - 1/4 = ?
=1 2/4
=1 1/2

?是1 1/2

2,1/2-1,3/4-x=1/4

2,2/4-1,3/4-x=1/4

3/4-x=1/4

x=2/4

?=2/4

2-1/2 - 1-3/4 - x = 1/4
x = 2-1/2 - 1-3/4 -1/4
x = 2 -1/2 - 2
x = 1/2