取数字的小数部分问题，请高手帮忙！

我写了一个函数
Public Function dzh(du As Double) As Double()
    Dim rst(3) As Double
    Dim tem As Double
    rst(0) = Fix(du)
    tem = (du - rst(0)) * 60
    rst(1) = Fix(tem)
    rst(2) = (tem - rst(1)) * 60
    dzh = rst
End Function
调用函数时参数值为105.26，为什么du-rst(0)等于0.260000000005而不等于0.26呢？怎么解决啊？