两个浮点数数相加的语句怎么写？

[bhut]

totalenergy=0
totalenergy=totalenergy+energy
这样的语句得到的结果却是不精确的，totalenergy和energy小数点后都是5位数，
相加的结果变成6位数

[Brookes]

totalenergy=0.0
totalenergy=totalenergy+energy

[bhut]

这样也不行

[tohen]

<% set conn=server.createobject("adodb.connection")
conn.open "DRIVER={Microsoft Access Driver (*.mdb)};DBQ=" & server.MapPath("liandong.mdb")
set rs=server.createobject("adodb.recordset")
rs.open "select * from city",conn,1,1
%>
<form action="post" name="form1">省份：
<select name="province" onchange="changesmall(province.value)">
<option selected value="吉林">吉林</option>
<option value="湖南">湖南</option>
<option value="浙江">浙江</option>
</select>
城市：
<select name="cityname">
<option selected>长春</option>
<option>白山</option>
<option>吉林</option>
</select>
</form>
<script language="JavaScript">
var mycity = new Array();
<% for i=0 to rs.recordcount-1%>
mycity[<%=i%>] = new Array("<%=rs("province")%>","<%=rs("city")%>");
document.write(mycity[<%=i%>]);
document.write("<br/>")
document.write(mycity[<%=i%>][0]);
document.write("<br/>")
<%rs.movenext
next%>
function changesmall(provname){
var j=0;
var i;
for(i=0;i<<%=rs.recordcount%>;i++)
{
if (mycity[i][0]==provname)
{
form1.cityname.options[j].text=mycity[i][1];
j=j+1;}

}

}
</script>