Six minutes. Every variable in your apps lives somewhere. Today you find out where — and why it matters when your app breaks.
Tap a chip, then tap a bucket. Everywhere = any block in the app can get or set it. One block only = it exists only inside the handler or procedure it came from.
App Inventor lets you name a global and a local the same thing. These two set blocks are both called guesses. Which one changes the box the whole app shares?
A guessing game starts with GuessesRemaining = 10. The subtract-one block sits at the very top of GuessButton.Click, before any checks. The player taps Guess with the box empty three times, then makes two real wrong guesses. What does the label say?
Two names from your own app. Be exact — the real names you typed.
Global = one box the whole app shares. Any block can read it, any block can change it — which is exactly why bugs in globals are hard to find.
Local = a box that only exists inside the block that made it. Fewer places can touch it, so fewer places to look when it breaks.
Today you build a two-player guessing game with two globals (the secret number and the guesses left) and one local (the guess the player just typed). Then the real job: find the variable in your game that should have been local, and fix it.
Step 3's answer: 5. The blanks got counted. Moving one block is the fix — you'll do it today.