Grade 10 · Theory
Common file types and extensions
Data representation, storage and social implications · about 3 min
Visual overview: Common file types and extensions1 MIN READ
2 study sections · pause after each one and recall the key ideaA file extension tells the operating system (and you) what kind of data a file holds and which program should open it.
Key points- Documents: .docx (Word), .pdf (fixed-layout document), .txt (plain text), .rtf.
- Spreadsheets and data: .xlsx, .csv (comma-separated values — used for data exchange).
- Images: .jpg (photos, lossy), .png (lossless, supports transparency), .gif (animation), .bmp.
- Audio/video: .mp3, .wav, .mp4, .avi.
- Programs and archives: .exe (executable), .zip (compressed archive).
- Lossy compression discards detail permanently (jpg, mp3); lossless keeps everything (png, zip).
- Extension — the suffix after the last dot in a filename.
- Lossy vs lossless — whether compression sacrifices quality for size.
EXAM TIP
pairs like "photo for a website" → .jpg and "logo needing a transparent background" → .png come up often.