Educational Cards
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The golden coin game
In this take-away game you start with a pile of tokens and each turn remove between 1 and k of...
Nim and the nim-sum
Nim has several rows of counters. Each turn a player removes any number of counters from a single...
The colour of a square from its coordinates
Every square is light or dark, and you can tell which without looking at a board. Number the files...
Northcott's game is Nim in disguise
Northcott's game puts a black and a white piece on each row of a board; on your turn you slide your...
Twelve knights guard the board
What is the fewest knights that together attack every empty square? That minimum is the knight...
Each square has a name
The board is a coordinate grid. The eight columns are files , labelled a to h from White's left....
Piece values as numbers
Give each piece its standard value: pawn 1, knight 3, bishop 3, rook 5, queen 9. Now the pieces are...
Balancing two armies
Build two armies of equal total value from the piece values pawn 1, knight 3, bishop 3, rook 5,...
The eight queens puzzle
Place eight queens so that no two attack each other: none sharing a rank, file, or diagonal. Many...
Nicht angreifende Damen und Symmetrie
Zwei Damen greifen einander nicht an, wenn sie weder Reihe noch Linie noch Diagonale teilen. Mit...
The pigeonhole principle
The pigeonhole principle says that if you place more items than boxes, some box holds at least two...
Eine geheime Figur erschließen
Eine unbekannte Figur zeigt einige erreichbare Felder. Daraus soll ihre Zugregel erschlossen...