What is a variable?

Your loop challenge ended with a puzzle: how can a sprite count 1, 2, 3 when a loop repeats the same thing every time?

Here's the answer. The program needs somewhere to remember a value between repeats.

That somewhere is a variable — a named box holding one value. Put something in, look at it later, replace it whenever you like.

Every variable has two parts:

• A name you choose — score, lives, timer, speed
• A value it currently holds — 0, 3, 47

Two blocks do almost everything:

• set [score] to 0 — replace whatever is in the box
• change [score] by 1 — adjust what's already there

Use set to start fresh at the beginning of a game. Use change to count up or down as it's played. Mixing these up is a very common bug — set score to 1 every time a mango is caught leaves the score stuck at 1 forever.