-13×2/3-0.34×2/7+1/3×(-13)-5/7×0.34+3
=-13×2/3+1/3×(-13)-0.34×2/7-5/7×0.34+3
=-13*(2/3+1/3)-0.34*(2/7+5/7)+3
=-13-0.34+3
=-13.34+3
=-10.34
解:-13*2/3-0.34*2/7+1/3
*(-13)-5/7
*0.34
=-13*(2/3+1/3)-0.34*(2/7+5/7)
=-13-0.34
=-13.34
楼上的有一点错误,这个才对,用乘法分配【小学知识】来解,汗.....差点打配方【初3知识】