I'm new to this but I having trouble coding a math equation using randomObject.next

My code is:
Module MathQuiz
Sub Main()
'create random Mathequation
Dim randomObject As New Random()
Dim randomNumber As Integer = randomObject.Next() 'generate random number
Dim j As Integer
Dim k As Integer

'generate 20 random numbers between 1 and 15
For j As Integer = 1 To 15

Next
Console.Write()

For k As Integer = 1 To 15
Console.Write("randomObject.Next, k = 7")

If j And k Mod 15 = 0 Then

Console.WriteLine()
Console.ReadLine()

End If
Next
End Sub

End Module 'MathQuiz

There are several errors