完成下列长度单位换算,要求写出过程(用科学记数法表示):
(1)7400千米=________________=_____________米;
(2)2.4分米=________________=_____________厘米;
(3)6.78立方厘米=________________=_____________升;
(4)6.5×10的-8米=________________=_____________微米.