Here's all the code I have so far. This is for the entire program but the bit I'm stuck with at the moment is the Quadratic solver:

Module Module1

Sub Main()

    Do

        Dim intInput As Integer

        Console.WriteLine("")
        Console.WriteLine("Main Menu")
        Console.WriteLine("")
        Console.WriteLine("Select 1 for Quadratic Equation solver")
        Console.WriteLine("Select 2 for Monte-Carlo integration")
        Console.WriteLine("Select 3 for Prime number determination")
        Console.WriteLine("Select 4 to exit the program.")

        If Integer.TryParse(Console.ReadLine(), intInput) Then
            Select Case intInput
                Case 1
                    Console.WriteLine("Quadratic Equation solver")
                    Console.WriteLine("")
                    Dim coefA, coefB, coefC, x1, x2 As Double
                    'Single type requires 4 bytes for storage compared to Double's 8, so it could be implemented here.
                    'However, Single is limited to 7 digits, meaning an accuracy of 5 d.p is not achievable with any number over 100.
                    Console.WriteLine("ax^2+bx+c = 0. Enter coefficients")
                    Console.WriteLine("A:")
                    coefA = Console.ReadLine()
                    Console.WriteLine("B:")
                    coefB = Console.ReadLine()
                    Console.WriteLine("C:")
                    coefC = Console.ReadLine()
                    x1 = (-coefB + Math.Sqrt(coefB ^ 2 - 4 * coefA * coefC)) / (2 * coefA)
                    x2 = (-coefB - Math.Sqrt(coefB ^ 2 - 4 * coefA * coefC)) / (2 * coefA)
                    Console.WriteLine("X is equal to " & x1 & " or " & x2)
                Case 2
                    'code for monte-carlo integration here
                Case 3
                    'code for Prime number determination here
                Case 4
        Exit Sub
                Case Else
        Console.WriteLine("Please enter a value between 1 and 4")
            End Select
        Else
            Console.WriteLine("Please enter a value between 1 and 4")
        End If
    Loop

End Sub

End Module