Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

Create a free account to open Inside the microcontroller. The free chapters of Embedded Systems and the Internet of Things stay readable without one.

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Set Cardinality Sprint

Count a power set's subsets, apply inclusion-exclusion for |A∪B|, or read off |A∩B| from two explicit sets -- all closed-form, all fast.

⏱️ 60s

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