(-1/2)—(+3/5)—(—1/9)+(-3/8)
同号为正,异号为负.
=-1/2-3/5+1/9-3/8
=-(5/10+6/10)-(27/72-8/72)
=-11/10-19/72
=-(396/360+95/360)
=-491/360
=-1又131/360
(-1/2)—(+3/5)—(—1/9)+(-3/8)
同号为正,异号为负.
=-1/2-3/5+1/9-3/8
=-(5/10+6/10)-(27/72-8/72)
=-11/10-19/72
=-(396/360+95/360)
=-491/360
=-1又131/360