{"id":"study-spending-multiplier-show-math","audience":"high-school","category":"explaining","technique":"examples","track":"study","title":"See the spending multiplier worked out with your class numbers","free":false,"task":"AP Macro's spending multiplier confuses you. Get exactly 3 numbered lines: the multiplier calculation with the numbers shown, the total change in GDP with the numbers shown, and one sentence on what it means for the town, plain text, under 70 words. Use the corrected MPC from Mr. Farouk's announcement.","materialLabel":"Your AP Macro notes (attached to your prompt automatically)","material":"AP MACRO - Mr. Farouk - Unit 3: The multiplier\n\nSpending multiplier = 1 / (1 - MPC)\nMPC = marginal propensity to consume = share of each extra dollar people spend.\nTotal change in GDP = multiplier x initial change in spending\n\nCLASS EXAMPLE: The town of Eastbrook builds a new $2 million community center. Construction workers spend part of their pay at local shops, shop owners spend part of theirs, and so on.\nSlide: MPC = 0.8 -> multiplier = 5 -> GDP rises by $10 million.\n\nANNOUNCEMENT (Mr. Farouk, Google Classroom): \"Correction to today's slide: the MPC for the Eastbrook example is 0.75, not 0.8. Please redo the example before the quiz.\"\n\nMy confusion: how does $2 million turn into way more than $2 million?\n\nNot on this quiz: tax multiplier, balanced budget multiplier (next week).\n\nQuiz Thursday. FRQ practice packet due Friday.","rules":[{"type":"numberedItems","count":3},{"type":"maxWords","max":70},{"type":"plainText"}],"mistakes":[{"title":"Asking for an explanation","why":"The AI explains the idea in words and may reuse the slide's old numbers.","fix":"Ask for the math: \"Show each calculation with the numbers.\"","checks":["r0","r1"]},{"title":"Missing the correction","why":"The slide's MPC and the corrected one are both in your notes.","fix":"Add: \"Use the corrected MPC of 0.75.\"","checks":["r0"]},{"title":"Not saying how many lines","why":"The AI picks its own number, and it usually picks more lines than you need.","fix":"Be exact: \"Exactly 3 numbered lines.\"","checks":["numberedItems"]},{"title":"Skipping the meaning","why":"Numbers alone don't answer your real question: how $2 million becomes more.","fix":"Add: \"End with one sentence on what it means for the town.\"","checks":["r2"]},{"title":"Trusting the AI to count words","why":"AI is bad at counting. Ask for a total and it often lands 20% over.","fix":"Cap each line: \"each under 20 words.\"","checks":["maxWords"]},{"title":"Forgetting where it will be read","why":"AI formats for a screen, with bold and headings that show up as stray symbols in your notes.","fix":"Say: \"Plain text, no bold, no headings.\"","checks":["plainText"]}],"promptHints":[{"label":"Asks to show the math","patterns":["show.{0,15}(math|numbers|calculation)","1 ?/ ?\\(1","x \\$?2"]},{"label":"Uses the correction","patterns":["0?\\.75","correct","announcement"]},{"label":"Says how many lines","patterns":["\\b(3|three)\\b.{0,25}line"]},{"label":"Asks what it means","patterns":["what it means","re-?spen","meaning","town"]},{"label":"Sets a length limit","patterns":["\\d+\\s*words","word (limit|count)","under \\d+"]}],"hint":"Seeing the numbers plugged in is what makes the multiplier click. Ask for each calculation on its own line, the corrected MPC, and a one-sentence meaning.","rubricLabels":["Line 1 shows the multiplier with the corrected MPC: 1 / (1 - 0.75) = 4 (not 5)","Line 2 shows the total change in GDP: 4 x $2 million = $8 million (not $10 million)","Line 3 explains in one sentence that the first spending gets re-spent around town, and no tax or balanced budget multiplier appears"]}