在学习《二次根式》之前,同学们已经学习了《实数》、《分式》和《整式的乘法与因式分解》等章节.通过《实数》一章的学习,大家对数的认识从有理数范围扩大到了实数范围,并对实数的加减运算的性质和法则有了初步的感受.在《二次根式》的学习中,我们会继续探索实数的乘除运算,并体会到有理数的运算律和运算法则在实数范围内仍然成立.不仅如此,由于数式相通,所以当将二次根式看成字母时, Students have learned the chapters of “real number”, “fractional number” and “integral multiplication and factorization” before they learn “second root style.” Through the study of Chapter “Real Number,” everyone knows the number from The range of rational numbers expands to the range of real numbers, and has a preliminary experience of the nature and rules of the addition and subtraction of real numbers.We will continue to explore the multiplication and division of real numbers in the learning of “quadratic roots” and realize that the arithmetic of rational numbers And the algorithm is still true in the real range is established. Not only that, because of the same type of numbers, so when the root quadratic as a letter,