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
答
==5/7(3/2+5/2—1/2)==5/7*7/2=2.5
答
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