1.
3/6+2/6=5/6

2.
1/5+1/3的结果比较接近1/2

3/4+2/5      
=15/20+8/20
=23/20

1/5+1/3
=8/15

3/4-1/2
=1/4

5/8-2/9
=45/72-16/72     
=29/72

3/10-1/11
=33/110-10/110
=23/110

5/7+1/4
=20/28+7/28
=27/28

3.
（1）√
（2）×
（3）×
（4）√

4.
解：x=5/6-3/6      
      x=1/3

解：x=11/55+25/55
x=36/55

1.
3/6+2/6=5/6

2.
1/5+1/3的结果比较接近1/2

3/4+2/5      
=15/20+8/20
=23/20

1/5+1/3
=8/15

3/4-1/2
=1/4

5/8-2/9
=45/72-16/72     
=29/72

3/10-1/11
=33/110-10/110
=23/110

5/7+1/4
=20/28+7/28
=27/28

3.
（1）√
（2）×
（3）×
（4）√

4.
解：x=5/6-3/6      
      x=1/3

解：x=11/55+25/55
x=36/55