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我们先来看看下面两个算式:68×43=2924;86×34=2924。你会发现:这两个算式每个因数的十位和个位上的数字交换了位置,但它们的积相等。非常好!其实我还要告诉你一个“秘
Let us first look at the following two formulas: 68 × 43 = 2924; 86 × 34 = 2924. You will find that the two formulas swap positions for each factor of ten and one digit, but their product is equal. Very good! In fact, I have to tell you a ”secret