Subtraction of Algebraic Expressions: Interactive Practice

① This example demonstrates the subtraction of algebraic expressions (including variable terms and constants) through randomly generated problems with immediate feedback, helping learners master removing parentheses and combining like terms. ② The core mathematical concept is subtraction of polynomials, involving sign handling (subtracting an expression is equivalent to adding its opposite) and combining like terms. ③ Construction highlights: GeoGebra commands Random, Textfield, and If are used; objects include a, b, c, s_1, InputBox1, button1, answer, d, text1_1, text1, A, B, text2, text3, forming a complete interactive practice interface. ④ Suitable for middle school algebra teaching and self-study, useful for classroom demonstrations or after-class practice, reinforcing rules through immediate feedback.