Russia 9 класс Informatics (basic)

Chapters: 4

1. Digital literacy

Internet and safety · Working in the information space

Cyber Crime and Cyber Safety – Cyber crime is any crime that uses a computer, phone or the internet as a tool or target. Common forms: hacking (breaking into a system without permission; ethical hackers test security with permission), eavesdropping (secretly intercepting communication), phishing (fake emails, SMS or websites that trick you into giving passwords, OTPs or card details), ransomware (malware that locks or encrypts files and demands money), cyber trolls (people who post provoking, offensive messages) and cyberbullying (harassing, threatening or humiliating someone online). Malware includes viruses (attach to files and spread), worms (spread by themselves), trojans (look useful but open a back door), spyware and adware (unwanted pop-up ads, often tracking). Safe browsing: https sites, updated software, antivirus and firewall, no unknown links or downloads. Identity protection: strong unique passwords, two-factor authentication, never sharing OTPs, careful sharing of personal details, and logging out on shared devices.

Modelling · Graphs and trees

Computer Simulation – A model is a simplified description of a real system that keeps only what matters. A computer simulation runs that model step by step in time to see what would happen. It has variables (the state), rules (how the state changes), parameters (numbers we can set) and often randomness, so we repeat runs and average. We check a simulation against real data (validation). Simulations are used for weather, traffic, disease spread, flight training and design, because they are cheaper, safer and faster than real tests, but they are only as good as their model and data.
Graph Theory: Dots, Lines and Networks – A graph is a set of vertices (dots) joined by edges (lines). The degree of a vertex is how many edges touch it, and the sum of all degrees is twice the number of edges. An Euler trail uses every edge once and exists only when 0 or 2 vertices have odd degree. A tree is a connected graph with no cycles and n − 1 edges. Weighted graphs model roads and networks; Kruskal’s and Prim’s algorithms find a minimum spanning tree.

Algorithm design · Arrays · Control and feedback

Programming Basics: Sequence, Selection, Loops and Functions – A program is a set of exact instructions a computer follows. Every program is built from three structures: sequence (steps in order), selection (if/else choices) and iteration (loops). Variables store values. Functions group code into reusable, named blocks, which makes programs modular and easier to test, debug and maintain.
Arrays and Lists: Storing Many Values in One Name – An array is a row of numbered boxes that share one name. Each box holds one value and has an index that starts at 0. We read or change a box with its index, visit every box with a loop (traversal), and use that loop for standard algorithms: sum, average, largest, count and linear search. A 2D array is a grid of rows and columns, read with two indexes and two nested loops. A fixed array has a set length; a list (Python list, Java ArrayList) can grow and shrink.
Robotics: How Robots Sense, Think and Act – A robot is a machine that senses the world, decides what to do with a program, and acts with motors. It has a body (structure), sensors, a controller, actuators, a transmission such as gears, and a power supply. Robots help in factories, hospitals, farms, homes and space.

Spreadsheets · IT in society

Spreadsheets in Accounting: Formulas, BRS, Schedules, Ratios and Charts – A spreadsheet is a grid of rows and columns where each cell can hold a number, a word or a formula. When one number changes, every formula that uses it updates by itself. Accountants use spreadsheets for bank reconciliation, depreciation and loan schedules, payroll, ratio analysis and charts.