五年级数学题~~~~~~~~

5/1 + 6/5 + 5/4 =5/1 + 5/4 + 6/5 =1 + 6/5, 即 1又6分之5

9/8 + 7/4 - 9/8 = 9/8 - 9/8 + 7/4 =7/4

7/2 - 8/1 + 7/5 = 7/2 + 7/5 - 8/1 =1 - 8/1 =8/7

5 - 4/1 - 4/3 = 5 -（ 4/1 + 4/3 ）=5 - 1 =4

10/3 +6/5 + 6/1 = 10/3 +（ 6/5 + 6/1 ）=10/3 + 1，即 1又10分之3

3/2 - 5/2 + 3/1 =3/2 + 3/1 - 5/2 =1 - 5/2 =5/3

5/1 + 6/5 + 5/4 =100/20 + 24/20 + 25/20 =149/20 =7.45
9/8 + 7/4 - 9/8 = 18/16 + 28/16 - 18/16 =28/16 =7/4=1.75
7/2 - 8/1 + 7/5 = 35/10 - 80/10 + 14/10 =-31/10 =-3.1
5 - 4/1 - 4/3 = 5 - (12/3 + 4/3)= 5 - 16/3 =15/3 - 16/3 =-(1/3)
10/3 +6/5 + 6/1 = 50/15+18/15+90/15=158/15
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