Russia 9 класс Informatics (advanced)

Chapters: 4

1. Digital literacy

Internet and web pages · Information security

Web Development: How HTML, CSS and JavaScript Build a Web Page – A web page is a set of text files. The browser (client) asks a server for them using a URL and HTTP. HTML gives the page its structure: headings, paragraphs, links, images, lists, tables and forms. CSS gives style: colours, fonts, spacing and layout. JavaScript gives behaviour: it reacts to clicks and changes the page. Responsive design makes one page fit both phones and computers. Good pages are also accessible, fast and safe.
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.

2. Theoretical foundations

Models and databases · Graphs

Database Concepts: DBMS, Relations and Keys – Keeping data in separate files causes duplication, inconsistency and poor security. A database stores related data in one organised place, and a DBMS (like MySQL) is the software that manages it. In the relational model, data is kept in tables (relations) made of columns (attributes) and rows (tuples); a domain is the set of allowed values of a column. A candidate key uniquely identifies each row; one is chosen as the primary key and the others are alternate keys.
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.

3. Algorithms and programming

Subprograms · Recursion · Sorting and binary search · Two-dimensional arrays

Recursion: Functions That Call Themselves – Recursion is when a function solves a problem by calling itself on a smaller version of the same problem. Every recursive function needs a base case, where it stops and returns an answer directly, and a recursive case that moves closer to the base case. Each call gets its own stack frame on the call stack; frames are removed as calls return.
Sorting Algorithms – A sorting algorithm puts a list in order. Bubble sort swaps neighbours, insertion sort slides each item into a sorted part, selection sort picks the smallest each time, and merge sort splits the list and merges sorted halves. Merge sort needs far fewer comparisons on long lists (about n log₂ n instead of about n²/2).
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.

4. Information technologies

Advanced spreadsheets · AI and future IT

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.
Emerging Trends: AI, IoT, Cloud and Blockchain – Emerging technologies are new tools that are changing how we live and work. AI lets machines do smart tasks; machine learning lets them learn from data; NLP lets them use human language. AR adds virtual things to the real world, VR replaces it. Robots sense, think and act. IoT devices with sensors create big data, which smart cities use. Cloud computing rents out IaaS, PaaS or SaaS over the internet; grid computing joins many computers for one big job. Blockchain keeps a shared record that is very hard to change secretly.