How do I print them double-sided?

Double-sided, flip on the long edge. Every front sheet is followed by its own already-mirrored back sheet, so print them in the order they come and every answer lands on its own card.

Can I edit the cards?

Yes, and that is half the point. Once you own the deck, the "Buy & edit" button here opens all 38 cards in the free flash card maker on this site — reword a definition, delete the ones you do not teach, add your own, and print at anything from two to nine cards a page, rather than the fixed eight of the PDF.

Can I print a set for every student?

Yes. Personal and classroom licence: unlimited printing, every class you teach, every year you teach it. It does not cover reselling the file or passing it on to a colleague.

What if I find a card that is wrong?

Tell us and we fix it, and we publish what changed. We have withdrawn a whole deck from sale for being out of date rather than quietly patch it.

Do I need an account?

No. $2.99 at Stripe, the file downloads on the way back, and the deck stays unlocked in this browser.

Printable flash cards

38 Common File Extensions flashcards, ready to print. $2.99, once.

One payment buys the deck twice over: the printable PDF and every card unlocked to play online. Eight to a sheet, cut guides on every card, and the answer sheet already mirrored so a long-edge duplex print puts every answer on the back of its own question. 15 pages, US Letter, black and white. Grades 6–12.

Both halves, one price. A single deck printable is $1.29 on the store shelf and unlocking a deck to play is $2.99 — $4.28 for the two. Here they are the same $2.99 purchase, so you save $1.29 — and there is one receipt to keep instead of two.

Includes every card unlocked to play online — $4.28 bought separately. One payment, no account, no renewal.

Same price, opens in the editor. Reword any card, add your own, print it your way.

Not sure yet? The first 30 cards of this deck are free to play and free to print, right now, with no email. Play the free 30 · Print the free 30

15 pages, and the backs are already right

Every front sheet is followed by its own back sheet with the rows reversed. Print double-sided, flip on the long edge, and answer number 7 is behind question number 7. Print a deck you built yourself, flip on the short edge, and every answer lands on the wrong card — which nobody finds out until sixty cards have been cut apart.

38 cards — counted out of the file, not rounded up
Eight cards a sheet, with cut guides
US Letter PDF, black and white, photocopier-friendly
Print a set per student, every class, every year

38 cards — the extensions a digital-literacy or computer-applications course actually handles. There are thousands more in the wild; listing obscure ones would be padding.

Every card here is cited to two independent sources

Two different organisations — not a standards body and a website reprinting it — and a script refuses the card if the two disagree, so the check runs on every card rather than on the ones somebody remembered to look at. A second specialist then re-verified this deck from sources of their own, without reading our citations first. A further 5,420 cards across 30 other decks were read end to end by a subject specialist instead, and we say which is which on every deck rather than averaging the two into one flattering word.

What 38 printed cards do that a screen does not

A phone deck is one card at a time. A printed deck is a pile you can split: the ones you know, the ones you nearly know, and the ones you keep missing. That third pile is the entire study session, and it is the thing a scrolling app hides from you.

Print once, use all year. The licence covers a set per student, every class, every year.
No device, no login, no data. Works in a cover lesson, on a bus, or at a kitchen table. Grades 6–12, filed under career, tech & modern.
Change what you disagree with. Every card loads into the free maker on this site. Reword it, drop it, add your own, reprint.

Here are the first 30 cards, written out

Check them against your own textbook before you spend anything. If you do not like how they are worded, do not buy the deck — that is what this list is for.

.pdf: Portable Document Format — fixed-layout document; opens in any PDF reader or a browser
.docx: Word document in Office Open XML — really a ZIP of XML parts; opens in Word or a compatible processor
.doc: The older Microsoft Word binary document format, superseded by .docx; Word still opens it
.rtf: Rich Text Format — formatted text that almost every word processor can read and write
.odt: OpenDocument text document (the ODF/ISO 26300 word-processor format); LibreOffice is its native app
.epub: EPUB e-book — a ZIP of HTML and CSS; opens in e-readers and e-book apps, not in a word processor
.xlsx: Excel workbook in Office Open XML; opens in Excel or a compatible spreadsheet program
.xls: The older Excel binary workbook format, superseded by .xlsx; Excel still opens it
.pptx: PowerPoint presentation in Office Open XML; opens in PowerPoint or a compatible slide app
.csv: Comma-separated values — a plain-text table; opens in a spreadsheet or any text editor
.txt: Plain text with no formatting; any text editor opens it (media type text/plain)
.json: JavaScript Object Notation — plain-text structured data; opens in any text editor
.xml: Extensible Markup Language — plain-text tagged data; read by editors and XML tools
.html / .htm: A web page in HyperText Markup Language; both extensions mean the same format
.css: Cascading Style Sheets — plain text that styles an HTML page
.js: JavaScript source code, plain text; runs in browsers and in server-side runtimes
.jpg / .jpeg: The same JPEG photo format under two spellings — lossy compression, no transparency
.png: Portable Network Graphics — lossless raster image with transparency; good for logos and screenshots
.gif: Graphics Interchange Format — raster image limited to 256 colours, and can be animated
.tif / .tiff: Tagged Image File Format — one format, two extensions; the usual choice for scanning and archiving
.svg: Scalable Vector Graphics — an XML vector image, so it scales to any size without going blocky
.webp: WebP raster image, lossy or lossless, designed for the web; browsers and modern image tools open it
.heic: A High Efficiency Image File (HEIF) holding HEVC-coded pictures; a common smartphone camera format
.psd: Adobe Photoshop document — keeps layers editable; a working file, not a delivery format
.mp3: MPEG audio — lossy compressed sound; plays in any media player (media type audio/mpeg)
.wav: WAVE audio, usually uncompressed PCM — big files, used for recording and mastering
.flac: Free Lossless Audio Codec — audio compressed with no loss of data at all, unlike MP3
.ogg: An Ogg container. The specs reserve .ogg for Vorbis; Opus should be .opus and other Ogg audio .oga
.mp4: MPEG-4 container, usually video with audio; audio-only MPEG-4 is registered separately as audio/mp4
.mov: QuickTime movie container for movie files; the .qt extension names the same format

Download all 38 cards — $2.99

The printable and every card unlocked to play — $4.28 bought separately, $2.99 together. One payment, no renewal, no account. Or take every deck: Study Pack, $11.99 a month — all 78 decks, all 7,178 cards, every printable, no ads. 5 single decks costs more than one month.

Includes every card unlocked to play online — $4.28 bought separately. One payment, no account, no renewal.

Same price, opens in the editor. Reword any card, add your own, print it your way.

Play it online insteadThe first 30 cards are free to play, with no account.Study Pack — $11.99/monthAll 78 decks and every printable.

Questions

How do I print them double-sided?: Double-sided, flip on the long edge. Every front sheet is followed by its own already-mirrored back sheet, so print them in the order they come and every answer lands on its own card.
Can I edit the cards?: Yes, and that is half the point. Once you own the deck, the "Buy & edit" button here opens all 38 cards in the free flash card maker on this site — reword a definition, delete the ones you do not teach, add your own, and print at anything from two to nine cards a page, rather than the fixed eight of the PDF.
Can I print a set for every student?: Yes. Personal and classroom licence: unlimited printing, every class you teach, every year you teach it. It does not cover reselling the file or passing it on to a colleague.
What if I find a card that is wrong?: Tell us and we fix it, and we publish what changed. We have withdrawn a whole deck from sale for being out of date rather than quietly patch it.
Do I need an account?: No. $2.99 at Stripe, the file downloads on the way back, and the deck stays unlocked in this browser.