Introduction

Welcome!

This lesson introduces the most essential beginner topics of Python programming.

Press the 'Next' button to proceed with the lesson.

Running code

On the right are two boxes. One is for writing code in. The other shows the result of running your code.

Press the 'Run Code' button and see what happens.

After running the code, you should see a number appear in the 'Output' box.

Then press 'Next' to continue to the next slide.

Using print

The code you ran used print to show the number 123 in the output box. Generally, print is one of the most-used commands in programming. It shows information on your screen. Without print, your program would show nothing when run.

Your first challenge is to change the code so it shows the number 2 in the output box when you run it.

Therefore, change the code in the code box from print(123) to print(2).

Then press 'Submit Answer' to check your solution before continuing.

Larger programs

Python programs can have more than one line. Some programs have hundreds of lines of code.

Here is an example of a program with two lines of code:

print(123)
print(456)

Python will run the lines one at a time, starting at the top. When a print is reached, the value between the parentheses is shown in the output box.

Try to run the code and see what it does.

Then change the code so that it prints 10 on the first line, and 100 on the next line. Submit your answer before continuing.

Using print from scratch

Now that you have seen some examples of using print, try writing a line of code from scratch. Your code should use print to show the number 42 in the output box.

You can refer back to previous slides if you don't remember exactly how to use print.

Note that upper- and lowercase letters, spelling, and parentheses must all be correct when writing code -- otherwise Python won't understand you. Make sure you follow the previous examples closely.

Basic addition

If you put a math expression into print then Python will calculate it for you before printing it.

Here is an example of code that calculates and prints 2+3:

print(2+3)

Use this as a basis for your own addition program.

To continue, write code that calculates 123 + 456 and prints the result.

Multiplying and subtracting

Next, use print twice. First calculate 42 * 56. Then calculate 88 - 512.

If you are not sure how to proceed, try pressing the Hint button.

More maths

Use a single print to do a calculation that uses both plus, times, and minus in one line.

If you need a hint, you can press the 'Hint' button.

Conclusion

Congratulations on completing the first lesson! You are now familiar with using print and working with numbers in Python.

The rest of the course covers all the fundamental concepts you'll need to become competent at programming.

The next lessons introduce strings - a way to represent text - and variables, which let you store values for later use.

Keep learning