This very simple subtraction math game is called Räkna riddare ("Count Knights") on the box and "Minusleken" ("The Minus Game") in the rules.
Players are dealt a number of cards which come in two types, subtraction questions (e.g. "9-2" or "6-4") and results numbered 0-8. One player states a question from one of their cards, and the other players should call out the correct answer providing they hold a corresponding card. The rules contradict themselves on the subject of drawing cards and hand sizes, but basically you keep matching pairs and drawing. The rules are also inconsistent between languages when to end the game: either when all cards have been drawn, or until no more matches can be made between hands. At this point matching pairs in hand are added to pairs taken during play and the player with the most pairs wins.
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