{"id":"study-compound-interest-year-by-year","audience":"high-school","category":"explaining","technique":"examples","track":"study","title":"See compound interest worked out year by year","free":false,"task":"In Personal Finance class you get the compound interest formula but not what it does. Get exactly 3 numbered lines, one per year for the class example, each showing the multiplication like 'Year 1: $500 x 1.04 = $520', then one sentence comparing the year 3 total with simple interest, plain text. Use the corrected rate from Mr. Haddad's email.","materialLabel":"Your class notes and the teacher's email (attached to your prompt automatically)","material":"PERSONAL FINANCE (elective) - Mr. Haddad - Unit 3: Saving\n\nCompound interest: you earn interest on your interest. Each year, the new balance = old balance x (1 + rate).\nSimple interest: you only earn interest on the starting amount. Interest each year = starting amount x rate.\n\nCLASS EXAMPLE (slide 9): Jada puts $500 in a savings account at 5% interest, compounded once a year, for 3 years. She doesn't add or take out money.\n\nSimple interest version: $500 x 0.05 = $25 per year, so $575 after 3 years.\n\n---\nEMAIL from Mr. Haddad (Tues):\n\"Slide 9 typo: the rate in Jada's example is 4%, not 5%. Please redo the example at 4% for the worksheet. Simple interest at 4% would be $20 a year, $560 after 3 years.\"\n\n---\nMy confusion: why does the interest get bigger each year if the rate stays the same?\n\nWorksheet due Friday. Field trip to the credit union next week, permission slip due.","rules":[{"type":"numberedItems","count":3},{"type":"maxWords","max":70},{"type":"plainText"}],"mistakes":[{"title":"Asking for an explanation","why":"The AI explains the formula in words, which is the part you already get.","fix":"Ask to see it: \"Show each year's multiplication, one line per year.\"","checks":["r0"]},{"title":"Not saying how many year lines","why":"The AI picks its own number, and it usually picks more year lines than you need.","fix":"Be exact: \"Exactly 3 numbered year lines.\"","checks":["numberedItems"]},{"title":"Missing the email fix","why":"The typo and the correction are both in your material.","fix":"Add: \"Use the corrected 4% rate from the email.\"","checks":["r1"]},{"title":"No comparison","why":"Without the simple interest comparison, you don't see why compounding matters.","fix":"Add: \"End with one sentence comparing to simple interest.\"","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":"Fix the shape: \"3 lines like 'Year 1: $500 x 1.04 = $520', then one sentence.\"","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 each year","patterns":["each year","year by year","year 1","per year"]},{"label":"Shows the line shape","patterns":["x 1\\.04","like ['\"]","multiplication","format"]},{"label":"Uses the correction","patterns":["4%","correct","email"]},{"label":"Asks for the comparison","patterns":["simple interest","compar"]},{"label":"Sets a length limit","patterns":["\\d+\\s*words","word (limit|count)","under \\d+"]}],"hint":"Seeing the math is what makes compounding click. Show the AI one line of the math you want, use the corrected rate, and ask for the comparison at the end.","rubricLabels":["Each of the 3 year lines shows the multiplication at 4% (1.04), with correct results: $500 x 1.04 = $520, $520 x 1.04 = $540.80, $540.80 x 1.04 = about $562.43","Does not use the 5% typo anywhere","Ends with one sentence comparing the year 3 compound total (about $562.43) with simple interest ($560), with no extra lines before the year lines"]}