option explicit
 
dim prime as boolean
dim number as integer
dim x as integer
 
num = inputbox("Enter a whole number up to 100")
 
for x = 1 to 100
 
(code here)
 
next x

 
Do while true
 
   Dim x as Long
   Dim myNum as long
   myNum = val(InputBox ("Enter A Number"))
 
   Dim mFlag as Byte
   mFlag = 0
 
   For x = 1 to Clng(myNum/2)
      If myNum Mod x = 0 then
         mflag = 1
         exit for
      end if
   next
   if mflag = 0 then
      Msgbox "Prime Number"
      Exit sub
   end if
loop

For x = 2 to Clng(myNum/2)
....

Input number: 100
100 / 2:      50
Sqr(100):     10

Function IsPrime(checkValue As Long) As Boolean
     For testValue = 2 To CLng(Sqr(checkValue)) Step 1
         If checkValue Mod testValue = 0 Then
             IsPrime = False
             Exit Function
         End If
     Next
     IsPrime = True
 End Function

Sub Main()
    Do
        userValue = CLng(InputBox("Enter a value to test.  I will tell you if it is prime or not.", "Prime Tester", userValue))
        If IsPrime(userValue) Then
             If MsgBox(userValue & " is a prime number!  Congratulations!  Would you like to try another?", vbYesNo, "Number is Prime!") = vbNo Then
                End
            End If
        End If
    Loop
End Sub

Sub Main()
    Do
        userValue = CLng(InputBox("Enter a value to test.  I will tell you every prime up to (and possibly including) it.", "Prime Tester", userValue))
        primesList = "1"
        For countValue = 2 To CLng(userValue) Step 1
                If IsPrime(CLng(countValue)) Then
                    primesList = primesList & ", " & CStr(countValue)
                End If
        Next
        If MsgBox("The prime numbers up to (and possibly including) " & userValue & " are:" & vbCrLf & primesList & vbCrLf & vbCrLf & "Would you like to try another?", vbYesNo, "Your Prime Numbers") = vbNo Then
            End
        End If
    Loop
End Sub