Lesson 1: Review

In the first three lessons, we learned how to print content, use variables and operations, and work with strings. Now think: if I want the user to type a number and let the computer calculate, what should we do?

Now we type:

print("3" + "4")
print(3 + 4)

We will find the difference between them, the first line prints 34 but the second line prints 7. So in the fourth unit, we will learn why is there such a difference and how to use them to print different results.