🐍 Coding Intro

Scratch & Python Basics

⏱ 3 hr3 topicsInteractive

🎯 By the end: You can describe how Scratch builds programs from blocks, write a simple Python program that prints output, use int/float/string data, and do arithmetic in Python.

Programming means giving a computer step-by-step instructions. You'll meet two friendly ways in: Scratch, where you drag blocks together, and Python, where you type short, readable code. The best part — you can run real Python right here on the page.

1Scratch — coding with blocks

Scratch is a visual programming language where you build programs by snapping together coloured blocks — no typing of code needed. It's great for learning the ideas of programming.

Term	Means
Sprite	A character/object you control on the stage
Script	A stack of blocks that runs in order
Blocks	Motion, Looks, Sound, Events, Control, Pen, etc. — each does one thing
Stage	The area where your sprites act

The Pen blocks let a sprite draw lines as it moves — combine them with motion and repeat (loop) blocks to draw squares, triangles and patterns.

Key points

Scratch is block-based: you snap coloured blocks together instead of typing code.
A sprite is a character; a script is a stack of blocks that runs in order.
The Pen blocks make a sprite draw as it moves — good for shapes and patterns.

2Your first Python program

Python is a real, widely-used language with simple, readable syntax. The classic first program prints a message with the print() function:

print("Hello, World!")

Whatever you put inside the quotes is shown on screen. Press Run below to execute real Python — then change the message and run it again:

Python Playground▶ runs real Python

main.py

print("Hello, World!")
print("My name is Vidaara")

Output

Click Run to execute.

Key points

print("...") displays the text inside the quotes on screen.
Python is typed code (unlike Scratch's blocks) but is simple and readable.
Text inside quotes is called a string.

3Data types and arithmetic

Every value in Python has a data type. The three you need now:

Type	Holds	Example
int	Whole numbers	25
float	Decimal numbers	3.14
string (str)	Text in quotes	"Vidaara"

You can store values in variables and do arithmetic with + - * / %. Run this and try changing the numbers:

Variables & arithmetic▶ runs real Python

main.py

price = 250      # int
qty = 3
total = price * qty
print("Total:", total)

pi = 3.14       # float
name = "Asha"   # string
print(name, "paid", total)

Output

Click Run to execute.

Key points

Data types: int (whole numbers), float (decimals), string (text in quotes).
A variable stores a value: total = price * qty.
Arithmetic operators: + - * / and % (remainder).

★ Practical: code a little

Using the Python playgrounds above:

Print your own name and class on two lines.
Make two number variables and print their sum and product.
Store a float (like a price) and a string (like an item) and print them together.
In Scratch (if available), use Pen + repeat blocks to draw a square.

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