为了便于理解代数中抽象的符号变化,人们设计了一些纸片作为计算文具.例如,用正方形代表 x2,用矩形代表 x,红色的一面代表正项,蓝色的另一面表示负项……见图1.解题方法图1这样设计纸片的大小是合理的: x×x的正方形纸片代表x2,x×1的矩形纸片代表x,1×1的正方形纸片代表1.例如 To make it easier to understand the abstract symbolic changes in algebra, people have designed some pieces of paper as computing stationery. For example, use squares for x2, rectangles for x, red for positive items, and blue for negative items... Figure 1. Problem solving method Figure 1 The size of a piece of paper is reasonable: x x x square pieces of paper represent x2, x x 1 rectangular pieces of paper represent x, and 1 x 1 square pieces of paper represent 1. For example