String Concatenation, Repetition, and len()
How do `+` and `*` build and stretch strings — and why is `"3" * 5` nothing like `3 * 5`?
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Feynman technique
Learn with the Feynman Technique
Explain each idea in your own words in handwriting, then upload a photo for AI critique. Two attempts per question — there's no "right" answer, only depth of understanding.