Lesson 0: Unit Introduction

The goal of this unit is to teach students how to use input() and print(), understand that input() returns a string by default, and learn basic type conversion with int() and str(). Through exercises such as a “mini calculator,” students will experience the full process of input, processing, and output.

The key point of this unit is mastering the use of input() and print(), as well as applying int() and str() for type conversion. The main difficulty lies in understanding the difference between "5" as a string and 5 as an integer, so that students can avoid common type errors when mixing text and numbers.