初中代数两次质的飞跃贵州省瓮安一中周承欢从算术数发展到有理数，又从有理数发展到用字母表示的代数式，是初中代数从简单到复杂，从具体到抽象的两次质的飞跃，也是初中学生学习代数的两大难关．教学时，教师怎样引导学生突破这两大难关呢？一、由算术数到有理数的飞跃... The two qualitative leap of junior middle school algebra The development of Zhou Chenghuan from the arithmetic number to the rational number, and from the rational number to the algebraic expression represented by the alphabet, is the secondary quality of junior high school algebra from simple to complex, from concrete to abstract. Leaps are two major difficulties for junior high school students to learn algebra. When teaching, how can teachers guide students to break through these two difficulties? First, the leap from arithmetic to rational numbers...