6.4÷2.5=（6.4x0.4）÷(2.5x0.4)=6.4x0.4=2.56或6.4÷2.5=(8/5)²=1.6²=2.56
6.4×0.25×12.5=20回答完毕~有疑问请追问~无疑问请点击【采纳】~祝学习进步\(^o^)/~~~
6.4/2.5=（6.4*4）/（2.5*4）=2.56
6.4÷2.5＝（6.4×4）÷（2.5×4）＝25.6÷10＝2.56
