Using a virtual balance scale in this online activity, the student solves a classic strategy puzzle by finding a counterfeit coin that is indistinguishable, except for weight, from a set of similar coins. Increasingly higher levels of difficulty are provided. At the easiest level, there are eight coins, and the student is challenged to find the counterfeit coin in two weighings. The student experiments with different combinations of coins to find a winning strategy. At the most challenging level, there are 12 coins, with the counterfeit coin either lighter or heavier than the others. The challenge is to find the counterfeit coin in three weighings. Instructions for using the manipulative, strategy tips, and a link to the NCTM standard for algebra are included. Copyright 2005 Eisenhower National Clearinghouse


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Informal Education,Process skills,Middle School,NSDL,oai:nsdl.org:2200/20120114184444757T,Grade 8,NSDL_SetSpec_1007936,Grade 6,Problem solving,Strategies,Education,Reasoning,Grade 7



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