说明：a分之b表示成“b/a”
原式=-|4+2/3-6-1/3|-(-2-1/5+4/5-2-4/5)
=-|4-6+2/3-1/3|-(-2-2-1/5+4/5-4/5)
=-|-2+(2-1)/3|-(-4-1/5)
=-|-2+1/3|-(-4-1/5)
=-(2-1/3)-(-4-1/5)
=-2+1/3+4+1/5
=2+1/3+1/5
=2+(5+3)/15
=2+8/15 即2又15分之8
-|4又2/3-6又1/3|-{（-2又1/5）-（-0.8）-2又4/5}
=-|-1又2/3|-(-2又1/5+0.8-2又4/5)
=-1又2/3+4又1/5
=2又15分之8
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