Drag rhythmic values into up to 8 beat blocks per line to build a drum groove, or click a tile then click a block to place it — handy on a trackpad.

🎵 Statistics Lesson 13: Addition Rule for Overlapping Events — Count Outcomes for 'A or B' Using Inclusion-Exclusion mess around all you want, nothing here saves
152 BPM
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Statistics, Lesson 13: Addition Rule for Overlapping Events

Math skill: Count Outcomes for 'A or B' Using Inclusion-Exclusion

How the beat teaches it: Every slot gives the outcome counts for A, for B, and for both at once — the count for 'A or B' is countA + countB - countBoth, so the overlap isn't counted twice. Build that many notes anywhere in the kit.

This is lesson 13 of 24 in RockBlocks Math, Statistics, a free course where every lesson turns a math idea into something you can count, hear, and play. The previous lesson, Addition Rule for Mutually Exclusive Events,” covered count Outcomes for 'A or B' When A and B Can't Both Happen. Next is Lesson 14, Conditional Probability.”

Every slot above (A, B, C, D) is its own question, and it’s a real, blank RockBlocks beat the whole time — the same drag-and-drop tiles, kit, tempo, sheet music, and drummer view as anywhere else on the site. Tap ❓ Questionin the corner to read the current slot’s problem, build your answer right in the grid, then tap ✓ Check Answerto grade it. Once you’re done, keep going: expand the beat, drop it into a Stack, or save a copy to your own page — nothing here overwrites the lesson itself, so every visitor still starts from the same blank slots.