Fourteen guides, in the order a first Python course actually teaches the material. Each one opens with the mistake people make, then explains the rule that prevents it. Every output on every page was executed on CPython 3.11, not remembered.
Read them in order if you are working through a first Python course. Jump straight to one if you already know which idea is costing you marks. Nothing here needs an account, and nothing is behind a paywall.
Four question shapes, one table, and a two-week plan. Rereading the chapter is not one of them.
The words a first exam opens with, and the one Python behaviour that makes them real: a typo stops everything before line 1, a bad name waits for its line.
input() always hands you a string. That one fact explains most of the errors in a first program.
Oval, parallelogram, rectangle, diamond: what each shape means, the arrow that goes back up and makes a loop, pseudocode, and turning a chart into Python.
Three kinds of wrong, seven errors worth knowing by name, and the reading order that makes sense of them.
A robot with a pen: moving and turning, the 360 / n rule that draws any shape, colours and fills, functions, and two turtles as two objects.
The stop value is excluded, the accumulator has to accumulate, and a nested loop can be traced reliably if you write down the right two columns.
import and the dot, math and random, seeds that make dice repeatable, your own module with __name__, and the file name that breaks import.
A function that prints looks right and fails every test. A local variable vanishes the moment the call ends. Both cost marks, and neither looks like a mistake on screen.
number == 5 or 6 or 7 compiles, runs, raises nothing, and is true for every possible value. Plus truthiness, elif chains and why floats break ==.
s.upper() ran, produced the right answer, and threw it away. Plus negative indexes, slicing, traversal, .format() and f-strings.
y = x does not copy a list. It gives the same list a second name. The idea intro Python tests hardest, because you can get it wrong without anything crashing.
Opening a file for writing empties it before you write a byte. Plus key-value lookup, KeyError, .get(), the counting idiom and try/except/else/finally.
Find the biggest, keep and change, count, sort, pair up and work through records: comprehensions, get, sorted vs sort, zip and lists of dictionaries.
Reading an explanation is not the same as being able to produce the answer under time pressure. The free Python app draws from 500 written questions, every one with a worked explanation, and you can select the topic you just read about. It runs offline, keeps your progress on your own machine, and asks for nothing.
Deep links into practice · Types and conversion · Named runtime errors · Logical operators · Tracing code · List aliasing · Functions · String slicing · Dictionaries
The fourteen guides above cover every topic a first Python course examines. Since 2026-10-11 the practice bank covers every one of the eighteen sections. It keeps growing behind the guides, starting with the sections that are examined most heavily.
Practice topics getting more questions next · Functions · for loops and range · while loops · Strings
Topic-selectable practice with worked explanations. Offline, no ads, no account.
Start practising →Looking for a different subject? The full guide catalog covers Java, Discrete Math, Calculus and CompTIA Security+ as well, and every subject has its own free practice app under practice tests.
