求简便方法计算下列式子(过程要,都能简便)(1)(-0.5)+(9/2)+(-19/2)+9.75 (2)(-1/2)+(-2/5)+(+3/2)+(18/5)+(39/5)(3)(-8)+(-1.2)+(-0.6)+(-2.4)(4)(-3.5)+(-4/3)+(-3/
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求简便方法计算下列式子(过程要,都能简便)(1)(-0.5)+(9/2)+(-19/2)+9.75 (2)(-1/2)+(-2/5)+(+3/2)+(18/5)+(39/5)(3)(-8)+(-1.2)+(-0.6)+(-2.4)(4)(-3.5)+(-4/3)+(-3/
求简便方法计算下列式子(过程要,都能简便)
(1)(-0.5)+(9/2)+(-19/2)+9.75
(2)(-1/2)+(-2/5)+(+3/2)+(18/5)+(39/5)
(3)(-8)+(-1.2)+(-0.6)+(-2.4)
(4)(-3.5)+(-4/3)+(-3/4)+(+7/2)+0.75+(-7/3)
求简便方法计算下列式子(过程要,都能简便)(1)(-0.5)+(9/2)+(-19/2)+9.75 (2)(-1/2)+(-2/5)+(+3/2)+(18/5)+(39/5)(3)(-8)+(-1.2)+(-0.6)+(-2.4)(4)(-3.5)+(-4/3)+(-3/
求简便方法计算下列式子(过程要,都能简便)
(1)(-0.5)+(9/2)+(-19/2)+9.75
=(9/2-19/2)+(-0.5+9.75)
=-5+9.25
=4.25
(2)(-1/2)+(-2/5)+(+3/2)+(18/5)+(39/5)
=(-1/2+3/2)+(-2/5+18/5+39/5)
=1+11
=12
(3)(-8)+(-1.2)+(-0.6)+(-2.4)
=(-8-1.2)+(-0.6-2.4)
=-9.2-3
=-12.2
(4)(-3.5)+(-4/3)+(-3/4)+(+7/2)+0.75+(-7/3)
=(-3.5+7/2)+(-4/3-7/3)+(-3/4+0.75)
=0-3又2/3+0
=-3又2/3