Sub PrimeNb() Dim IsPrimeArray(1000) Dim i Dim j, jMax Selection.TypeText ("***** PRIME NUMBERS: ") '----- LOOP 1 , On each number For i = 1 To 1000 '----- Could be a prime number IsPrimeArray(i) = True '----- LOOP 2 , Search a divisor j = 2 jMax = i \ 2 '--- Int div While IsPrimeArray(i) And (j <= jMax) '----- "j" can divide "i" ? If (i Mod j) = 0 Then IsPrimeArray(i) = False End If j = j + 1 Wend '----- Display only prime numbers If IsPrimeArray(i) = True Then Selection.TypeText (i & " ") End If Next i ' ' [<-- i -->] ' [<-- j -->] ' .#.....................#.........................# ' | | | ' 2 i div 2 1000 ' End Sub