Post 2 (9/28/2014) - a LOT of scratch

These last two weeks have just been programming or analyzing scratch

One of the things we have been doing is to discover where a number is after a program. Example follows:

When space key pressed
   Set X to 4
   Set Y to 7
   Repeat 4
      If X>Y
         Set Y to Y + X
         Set X to X - 1
      Else
         If Y>X
            Set X to X + Y
            Set Y to Y - 1
         Else
            Add 10 to Y
   Say Join (X)(Y)

To discover the result, you could make it and see, or you could work through it. Example Continues

So, at the first part, X = 4 and Y = 7

Then the first loop plays
   first it checks, Is X greater than Y? NO
   this places it into the "Else" category
      now it checks, Is Y greater than X? YES
         now it makes X equal X + Y. 4 + 7 = 11
         now it makes Y equal Y - 1. 7 - 1 = 6
Now it repeats the loop
   first it checks, Is X greater than Y? YES
      now it makes Y equal Y + X. 6 + 11 = 17
      now it makes X equal X - 1. 11 - 1 = 10
3rd repeat
   first it checks, Is X greater than Y? NO
   this places it into the "Else" category
      now it checks, Is Y greater than X? YES
         now it makes X equal X + Y. 10+ 17 = 27
         now it makes Y equal Y - 1. 17 - 1 = 16
4th (and final) repeat
   first it checks, Is X greater than Y? YES
      now it makes Y equal Y + X. 16 + 27 = 43
      now it makes X equal X - 1. 27 - 1 = 26

Now comes the Say command
   Join means list them (in that order), so if X was he and Y was llo, join (X)(Y) would result in "hello"
   In this case,  X = 26 and Y = 43, so it would say "2643"