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🔁 Loops — learning path
🔁 Beginner16 problemsFree · no login needed
What this path teaches
range() bounds, off-by-one errors, infinite while loops, break vs continue, and the loop variable that outlives its loop. Loops are where most beginner bugs concentrate — this path drills every classic shape.
By the end: You can state a loop's first value, last value, and iteration count before running it.
Your progress
0 of 16 opened
Start the path →The problems, in order
- 1Print Numbers from 1 to 5
- 2Print Even Numbers
- 3Countdown
- 4range() with wrong bounds
- 5Off-by-one loop error
- 6Looping one step too far
- 7Off-by-one when counting down
- 8Looping over a number instead of a sequence
- 9Infinite while loop — forgot to update the counter
- 10break vs continue
- 11break inside the wrong loop
- 12for loop with range and step
- 13enumerate with a start value
- 14Loop variable after the loop ends
- 15else clause on a for loop
- 16Nested loop with a shared variable
How to work a path
Do the problems in order — each one assumes the rule taught by the one before it. Open a problem, try it in the interactive editor, and only then read the explanation. Progress is saved in this browser automatically (signed-in solves also earn XP and streaks). One path per week is a solid pace; finishing in a single sitting is allowed but not required.