简算:1.5×5/7-(-5/7)×2.5+(-0.5)×5/7

问题描述:

简算:1.5×5/7-(-5/7)×2.5+(-0.5)×5/7

==5/7(3/2+5/2—1/2)==5/7*7/2=2.5

1.5×5/7-(-5/7)×2.5+(-0.5)×5/7
=1.5×5/7+5/7×2.5-0.5×5/7
=5/7×(1.5+2.5-0.5)
=5/7×3.5
=5/7×7/2
=5/2
=2.5