130 counting up

Here's some code useful to study:


to countup :n
   make "count 0
   while [:count < :n] [
      make "count :count + 1
      print :count
      wait 50
   ]
   print (sentence "Finished "counting "to :n)
end


Can you make it count by 2? By 5? Add a variable so that "countup 30 5" (for example) would count to 30 by 5's? Can you write countdown?