Unlike any other balance, this balance lets you demonstrate that -1<0. Weights placed on the outer pans represent negative integers, and those placed in the inner pans represent positive integers, making it possible to demonstrate that (-1) + (+1)=0. Great for small group work, comes with 4 plastic pans, 4 plastic containers, a set of plastic weights and a Teaching Guide. Some assembly required. Grades 6 and up.
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