153 BPM
Loading drum sounds…+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
4/4 ×2
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.
Math skill: Count Passwords Excluding an All-Same Pattern
How the beat teaches it: The last lesson of Discrete Math: every slot counts all length-2 passwords from n symbols (n² total, by the multiplication principle), then subtracts the n passwords where both characters are the same — counting by complement, tying together sets, counting, and the whole course. Build that many notes anywhere in the kit.
This is lesson 24 of 24 in RockBlocks Math, Discrete Math, a free course where every lesson turns a math idea into something you can count, hear, and play. The previous lesson, “The Multiplication Principle,” covered multiply Option Counts Across Independent Choices. It is the final lesson in this grade.
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.