Computer Applications / IT: Fundamentals and Practical Skills
Computer Applications / Information Technology tests digital fundamentals and practical office and internet skills: number systems, hardware and software, operating-system tasks, word processing and spreadsheets, presentation tools, database concepts, networking and cyber safety.
Core rules
- Number systems: binary is base 2, octal base 8, decimal base 10, hexadecimal base 16. Each hexadecimal digit represents four binary bits.
- Hardware is physical; software is instructions-system software (operating system, utilities) and application software (word processor, spreadsheet).
- In a database, a primary key uniquely identifies a record; a foreign key links to a primary key in another table.
- A spreadsheet formula begins with =; relative references (A1) change when copied, absolute references ($A$1) do not.
- Networks are described by topology (star, bus, ring), by scale (LAN, WAN) and by protocol (HTTP/HTTPS, FTP, SMTP).
- Use strong passwords, verify URLs, avoid unknown attachments and back up data.
Worked example
Convert binary 1101.101₂ to decimal. Integer part: 1×8 + 1×4 + 0×2 + 1×1 = 13. Fractional part: 1×0.5 + 0×0.25 + 1×0.125 = 0.625. Sum = 13.625₁₀. The reasoning is positional: each bit is multiplied by 2 raised to its place value, with negative powers after the point. In a spreadsheet, =B2*$C$1 copied from C2 to C3 still multiplies by C1 because the column and row are absolute.
Traps
Writing 1101₂ as thirteen without showing place values; confusing RAM (volatile working memory) with ROM (non-volatile firmware); treating a foreign key as unique; using relative references where a fixed rate is needed; and describing HTTPS as merely faster rather than encrypted.