-|-2/3-(+2/3)|-|(-1/5)+(-2/5)|
=-|-23-23|-|-15-25|
=-|-43|-|-35|
=-43-35
=-2915
|4/7-2/5|-|3/5-7/9|+|2/9-3/7|
=|635|-|-845|+|-1363|
=635-845+1363
=735
-|-2/3-(+2/3)|-|(-1/5)+(-2/5)|
=-|-23-23|-|-15-25|
=-|-43|-|-35|
=-43-35
=-2915
|4/7-2/5|-|3/5-7/9|+|2/9-3/7|
=|635|-|-845|+|-1363|
=635-845+1363
=735