VB编程问题～函数定义调用～

题目是这样的：随机产生10个范围在0~200的整形数，并设计两个按钮，分别实现求最大值和最小值；打印内容包括10个整数都建议在picture控件内输出。
附加要求：求最大值和最小值请编写成两个函数

我这样编为什么运行的时候说我函数定义错误……
Dim number(1 To 10) As Integer
Dim a As Integer
Dim b As Integer
Dim i As Integer
Dim max As Integer
Dim min As Integer

Public Function maximum(number() As Integer) As Integer
a = number(1)
For i = LBound(number()) To UBound(number())
If number(i) > a Then
a = number(i)
End If
Next i
maximum = a
End Function

Public Function minimum(number() As Integer) As Integer
b = number(1)
For i = 1 To 10
If number(i) < a Then
b = number(i)
End If
Next i
minimum = b
End Function

Private Sub Command1_Click()

For i = 1 To 10
number(i) = Int(Rnd * 200) + 1
Picture1.Print number(i)
Next i
End Sub

Private Sub Command2_Click()
max = maximun(number())
Text1.Text = max