Pythonoid
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Pythonoid PRO

Eleven more topics. One payment.

The first 3 topics — how code runs, making the dragon speak, and what it remembers — are free, start to finish. PRO is a one-time $49.99 purchase that unlocks everything after that: 11 more topics, plus the optional challenge track.

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topics
11
exercises
155
challenges
48
  • Topics 4–14 — if and loops through functions, errors and clean code
  • The optional challenge track, across every topic
  • No subscription. No renewals. No ads.

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What PRO unlocks

Topics 4 to 14, and the challenge track.

Tap a topic to see what it actually teaches. Each one runs the same cycle as the free topics — explained, asked, guided, then on their own — and closes with a challenge that combines the whole topic.

11topics51segments155exercises

4 (PRO)if / elif / elseThe Dragon Decides5 segments16 exercises

An if statement lets a program do something only in certain situations, instead of doing the same thing every time.

What it teaches

  • Comparison operators: >, <, >=, <=, ==, !=
  • True and False as real values
  • The if statement
  • elif for additional cases
  • else as the catch-all
  • Why the order of conditions changes the result

Segments, in order

  1. 1Asking questions about numbers4 exercises
  2. 2if, by itself3 exercises
  3. 3elif and else3 exercises
  4. 4The Dragon CouncilTopic challenge3 exercises
  5. 5Order and overlap3 exercises

Each segment: explain → ask → guided → practice. Numbers are exercises.

5 (PRO)for + range()The Dragon Repeats5 segments15 exercises

A for loop runs the same instruction several times, so a child writes one line instead of twenty.

What it teaches

  • The for loop
  • range(n) — counting from zero
  • Why range(n) never reaches n
  • Using the loop variable inside the loop
  • Building a running total across passes
  • Loops and if statements together

Segments, in order

  1. 1Doing something many times3 exercises
  2. 2What range() actually counts3 exercises
  3. 3Building up a total3 exercises
  4. 4The Dragon PatrolTopic challenge3 exercises
  5. 5Loops inside loops3 exercises

Each segment: explain → ask → guided → practice. Numbers are exercises.

6 (PRO)while loopsThe Dragon's Vigil5 segments15 exercises

A while loop repeats for as long as something stays true, which makes it the right tool when you do not know in advance how many times to go round.

What it teaches

  • The while loop
  • Conditions that change over time
  • Why a loop can run forever, and how to spot it
  • break — leaving a loop immediately
  • continue — skipping one pass only
  • Choosing between for and while

Segments, in order

  1. 1while — repeat until something changes3 exercises
  2. 2break — leaving early3 exercises
  3. 3continue — skipping just one3 exercises
  4. 4The Full Night PatrolTopic challenge3 exercises
  5. 5Boundaries and every-path updates3 exercises

Each segment: explain → ask → guided → practice. Numbers are exercises.

7 (PRO)ListsThe Dragon's Inventory5 segments16 exercises

A list holds several values under one name, in order, so a program can work with a whole collection instead of one thing at a time.

What it teaches

  • Creating a list
  • Indexing from zero
  • Slicing with [start:end]
  • append() — adding an item
  • remove() — taking an item out
  • What copying a list actually does
  • Looping over a list

Segments, in order

  1. 1Lists and indexing4 exercises
  2. 2Slicing — taking a piece3 exercises
  3. 3Changing a list3 exercises
  4. 4The Grand Inventory CheckTopic challenge3 exercises
  5. 5Real copies, and the None trap3 exercises

Each segment: explain → ask → guided → practice. Numbers are exercises.

8 (PRO)input()Talking to the Dragon Tamer5 segments15 exercises

input() is the one command that genuinely pauses a program and waits for the player to type something back.

What it teaches

  • Asking a question with input()
  • input() always returns text, never a number
  • Converting text to a number with int()
  • The TypeError from forgetting to convert
  • Comparing a converted number correctly

Segments, in order

  1. 1input() asks, and really waits3 exercises
  2. 2int() turns text into a number3 exercises
  3. 3What happens if you forget int()3 exercises
  4. 4The Dragon's Three QuestionsTopic challenge3 exercises
  5. 5Validating input3 exercises

Each segment: explain → ask → guided → practice. Numbers are exercises.

9 (PRO)DictionariesThe Dragon's Stat Sheet5 segments15 exercises

A dictionary is a stat sheet — a value looked up by its name, not by its position in a list.

What it teaches

  • Creating a dictionary and looking up a value by key
  • The difference between key-based and position-based lookup
  • Updating a key's value
  • Adding a brand new key
  • The KeyError from a missing key, and .get() with a default
  • Looping over a list of dictionaries

Segments, in order

  1. 1A dict is a stat sheet3 exercises
  2. 2Updating a stat, adding a new one3 exercises
  3. 3A missing key crashes — .get() doesn't have to3 exercises
  4. 4The Full Roster CheckTopic challenge3 exercises
  5. 5Tally and group3 exercises

Each segment: explain → ask → guided → practice. Numbers are exercises.

10 (PRO)FunctionsThe Dragon's Abilities5 segments15 exercises

A function lets you name a piece of code once and run it again as many times as you like.

What it teaches

  • Defining a function with def
  • Calling a function, and calling it more than once
  • Parameters that customise what a function does
  • return hands a value back — it does not display it
  • A function call finishes and your code continues afterward
  • Choosing whether a function should print or return

Segments, in order

  1. 1def gives your code a name3 exercises
  2. 2Parameters customise the ability3 exercises
  3. 3return hands a value back3 exercises
  4. 4The Dragon's Two AbilitiesTopic challenge3 exercises
  5. 5Lists leak out. Numbers don't.3 exercises

Each segment: explain → ask → guided → practice. Numbers are exercises.

11 (PRO)Error messagesThe Dragon's Diagnosis4 segments12 exercises

A Python error message already tells you what went wrong — this topic teaches how to actually read it.

What it teaches

  • Reading a traceback's last line first
  • Recognising IndexError, KeyError, TypeError, ValueError, ZeroDivisionError by name
  • Syntax errors vs. runtime errors vs. logic errors
  • Why a logic error produces no error message at all
  • A five-step debugging procedure: read, expect, observe, change one thing, rerun

Segments, in order

  1. 1Reading a traceback bottom-up3 exercises
  2. 2Name that exception3 exercises
  3. 3Syntax, runtime, and logic errors3 exercises
  4. 4The Debugging ProcedureTopic challenge3 exercises

Each segment: explain → ask → guided → practice. Numbers are exercises.

12 (PRO)AlgorithmsThe Dragon's Battle Plans4 segments12 exercises

The same handful of loop shapes shows up again and again in real programs — this topic gives them names.

What it teaches

  • The max-tracking and min-tracking patterns
  • The counter pattern, and how it differs from an accumulator
  • Search-with-a-flag, and finding a value's position
  • Why binary search needs a sorted list, and roughly how much faster it is
  • Selection sort, as a way to see how sorting actually works
  • Testing a pattern against an empty list, a single item, and identical values

Segments, in order

  1. 1Tracking patterns: max, min, and count3 exercises
  2. 2Search patterns3 exercises
  3. 3Sorting, and the edge cases every pattern needs3 exercises
  4. 4The Dragon's Full Hoard ReportTopic challenge3 exercises

Each segment: explain → ask → guided → practice. Numbers are exercises.

13 (PRO)Data structuresThe Dragon's Records4 segments12 exercises

The same information can be stored several genuinely different ways — this topic is about choosing which one fits the question you'll actually ask.

What it teaches

  • The same data as two parallel lists, a list of dicts, and a dict of lists
  • Looping over nested data, including a loop inside a loop
  • Updating a value that lives one level deep
  • Sets for removing duplicates and checking membership
  • Why a set's order isn't guaranteed, and when to use sorted()
  • Choosing the right structure for the question being asked

Segments, in order

  1. 1The same data, four shapes3 exercises
  2. 2Nested access and the two-level loop3 exercises
  3. 3Sets: no duplicates, fast membership3 exercises
  4. 4The Dragon CensusTopic challenge3 exercises

Each segment: explain → ask → guided → practice. Numbers are exercises.

14 (PRO)Clean codeThe Dragon's Cleanup4 segments12 exercises

A name never changes what code does — only whether a human reading it later can tell what it's for.

What it teaches

  • Why a variable's name never affects what a program computes
  • Magic numbers, and the real inconsistency bug they cause
  • Named constants as the fix — one value, one place it's defined
  • Spotting exact duplication vs. structural duplication
  • Extracting a repeated shape into a function with a parameter
  • Refactoring: changing how code looks without changing what it does

Segments, in order

  1. 1Naming as a thinking tool3 exercises
  2. 2Magic numbers and named constants3 exercises
  3. 3Spotting duplication3 exercises
  4. 4The Dragon's Messy FunctionTopic challenge3 exercises

Each segment: explain → ask → guided → practice. Numbers are exercises.

Optional · never requiredThe optional challenge track4 kinds48 challenges

Extra, harder puzzles for kids who want more — never required, never a prerequisite for anything else. They run across every topic: fixing a broken piece of code with no crash to point at, and solving something the obvious way before finding the shorter, better way to write the same thing.

  • Diagnosis

    Broken code with no crash to point at — find the bug by reasoning.

    For exampleThe Heal That Overshoots

  • Fewest Lines

    Solve it, then find the shorter, better way to write the same thing.

    For exampleA Loop Down to a Slice

  • The Long Hoard

    A longer task that composes three or more patterns at once.

    For exampleThe Most Common Drop

  • The Unseen Test

    Passes the case you can see — then a principled edge case is checked too.

    For exampleThe Grade Right on the Line

What stays free

The first three topics. All of them.

Every segment of topics 1 to 3 — 46 exercises — with no time limit and no card. The first level needs no account at all. PRO adds topics; not buying it never takes anything away.

  • Free

    Execution order

    How the Dragon Follows Your Code

    A program runs one line at a time, in the order it was written, and does nothing you didn't actually tell it to do.

    4 segments · 12 exercises · every one free

  • Free

    print()

    Making the Dragon Speak

    print() is how a Python program says something out loud, and it is the first real Python a child writes here.

    5 segments · 16 exercises · every one free

  • Free

    Variables

    What the Dragon Remembers

    A variable is a name Python remembers a value by, so the same value can be used again without writing it out every time.

    5 segments · 18 exercises · every one free

The same on every account, free or PRO

No ads, no analytics

No advertising anywhere and no analytics software of any kind. Nothing is sold or shared.

Help after three tries

After three failed runs, the game offers the solution — unasked, on every topic.

Locked means shown

PRO topics sit on the world map, marked — never hidden. You can see what you would be paying for.

Real Python, in the browser

Nothing to install. A child's code runs in the browser tab, never on our servers.

How buying works

Three steps — and one honest note.

Payments aren't switched on yet. Here is how buying will work, so nobody is surprised.

Checkout isn't connected yet

No payment provider is wired in yet. This step shows the real checkout once one is.

  1. 1

    Sign in, or make an account

    PRO belongs to an account. A visitor who isn't signed in is sent to register first — with Google, or an email and password — and comes back here afterwards.

  2. 2

    Press “Buy PRO — $49.99”

    PRO is attached to the account you're signed in with — only that account, and it only ever adds to it.

  3. 3

    Topics 4 to 14 open on the map

    So does the challenge track. Come back to this page later and the button is replaced by a note instead:

    PRO is already unlocked on your account.

Questions about PRO

Before you decide.

Privacy, ages and what an account stores are covered on the For parents page.

Is PRO a subscription?

No. It is a single one-time purchase of $49.99. There are no renewals and nothing to cancel.

What does a free account keep?

The first 3 topics — how code runs, making the dragon speak, and what it remembers — every segment, start to finish, with no time limit. Buying PRO adds topics; not buying it never takes anything away.

Can my child see the PRO topics before we buy?

Yes. Locked topics are shown on the world map and marked PRO, never hidden, and every one is listed on this page with what it actually teaches.

Do we need an account to buy?

Yes. PRO is attached to an account, so the button sends a signed-out visitor to register first — with Google, or an email and password.

Is the challenge track part of the course?

It is optional. The challenges are extra, harder puzzles for kids who want more — never required, and never a prerequisite for anything else.

Not sure yet? Start with the free three.

The first level takes about thirty seconds, and needs no account.

Play the first level free Back to the world map