Build a single-screen practice app for first-year management accounting students who can already define fixed and variable costs but hesitate on mixed and step costs. Show one cost item at a time. The student chooses one of four categories: fixed, variable, mixed, or step. Twelve items in total, three of each category, always in the same order. Write the twelve items in plain language, for example "Factory rent of 4,000 per month" and "A supervisor salary plus a bonus of 2% of output". Feedback appears immediately after each answer, before the next item: if the answer is right, say so and give a one-sentence explanation; if it is wrong, name the correct category, give the explanation, and add one line on why the chosen category does not fit. An answer cannot be changed once submitted. Show a running score in the form "4 of 7 correct". At the end, show the final score and list every item answered incorrectly with its correct category. A "Start again" button resets the score and returns to the first item.

Keep it to one screen, with no menus, tabs, or other pages to navigate to. Everything the app needs, including the questions, examples, answers, and feedback, must be built into the app itself. No sign-ins or student accounts, nothing saved after the page is closed, no connections to other websites or services, no AI running while students use it, and nothing that costs money. It should work on a phone as well as a laptop, be easy to read, and easy to reset and start again.

Build exactly what is described above and nothing else. Do not add extra features, screens, settings, or options, however useful they might seem. If something is unclear, choose the simplest version of it rather than the more capable one.

Build a single-screen practice app for undergraduates learning to proofread references. Show one reference at a time, formatted in APA style, with exactly one formatting mistake in it: a missing year, italics in the wrong place, authors out of order, or a full stop where a comma belongs. Break each reference into clickable segments so the student can click the part they believe is wrong. Ten references in total, with the type of error varying between them. When the student clicks, tell them immediately whether they found the error; either way, name the mistake, show the corrected version of that segment, and give a one-sentence rule explaining the convention. The student moves on with a "Next" button. Show a running score in the form "4 of 7 correct". At the end, show the final score and list every reference they got wrong with its error named. A "Start again" button resets the score and returns to the first reference.

Keep it to one screen, with no menus, tabs, or other pages to navigate to. Everything the app needs, including the questions, examples, answers, and feedback, must be built into the app itself. No sign-ins or student accounts, nothing saved after the page is closed, no connections to other websites or services, no AI running while students use it, and nothing that costs money. It should work on a phone as well as a laptop, be easy to read, and easy to reset and start again.

Build exactly what is described above and nothing else. Do not add extra features, screens, settings, or options, however useful they might seem. If something is unclear, choose the simplest version of it rather than the more capable one.

Build a single-screen practice app that trains students to estimate correlation from a scatterplot. Each round, draw a scatterplot of about forty points generated to a hidden correlation value between -1 and 1. The student estimates that value using a slider running from -1 to 1 in steps of 0.05, then presses "Check". Reveal the true value, the estimate, and how far apart they were, and say in one sentence what the pattern shown is typical of, for example that points this scattered usually indicate a weak relationship. Ten rounds in total, with a spread of strong positive, weak, near-zero, and negative relationships. Show a running average error across the rounds. At the end, show the average error over all ten and one line of advice based on whether the student tended to over-estimate or under-estimate strength. A "Start again" button resets everything and generates fresh plots.

Keep it to one screen, with no menus, tabs, or other pages to navigate to. Everything the app needs, including the questions, examples, answers, and feedback, must be built into the app itself. No sign-ins or student accounts, nothing saved after the page is closed, no connections to other websites or services, no AI running while students use it, and nothing that costs money. It should work on a phone as well as a laptop, be easy to read, and easy to reset and start again.

Build exactly what is described above and nothing else. Do not add extra features, screens, settings, or options, however useful they might seem. If something is unclear, choose the simplest version of it rather than the more capable one.