if we think we have to "teach" children what the schools call "basic arithmetic facts," e.g., that 3 + 4 = 7 and 5 x 4 = 20, a better way to do it is by having them discover for themselves, by experiment, as these two girls were doing, some of the basic properties of numbers. The statement that 3 + 2 = 5 is best understood, not as a statement about addition which someone invented and which can be learned only be being memorized, but as a statement about one property of the number 5. This property, that a group of five objects may be split up into a group of three objects and another of two
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