Compound Interest — the Snowball Effect
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The lab
⭐ SNOWBALL — A REAL-WORLD MONEY LAB ⭐
What students do
- The $1,000 Snowball — step into a real saving scenario with a clear “I can” target
- Decode Your Savings Statement — read an authentic annual statement showing balance growth
- Build the Snowball by Hand — compute each year's interest on the GROWING balance, not the original, no calculator
- Your Compound Interest Calculator — four “what-if” tasks, including a goal-seek and a counter-intuitive rate comparison
- Two Savings Accounts, Make the Call — prove that at an identical rate, compound interest still beats simple — and the gap grows
- Show What You Know — a scored mastery check on a fresh account
- Reality Check — reflection + a real-world connection
Real math, done right
The compounding work (7.RP.A.3, with an HS-extension note toward exponential functions) is done BY the student — twice, by hand, verified year-by-year against the closed-form formula. Every dollar figure is exact and cross-checked; the honest-number model flags 10% as a generous example (real savings rates run lower, real investing returns are typically higher over time).
Print or digital
Print-and-go, or assign the editable Word packet in Google Docs and the calculator in Google Sheets. No devices today? A Printed Calculator Readouts page lets a fully print-only class run the whole lab.
What is included
- 10-page student lab (PDF + editable Word)
- Self-calculating spreadsheet (Excel / Google Sheets)
- 3-page teacher guide with full answer key + 10-point rubric
- Printed Calculator Readouts (print fallback) + Terms of Use
More Money Labs
Standard codes refer to the Common Core State Standards for Mathematics. Math Class 678 is an independent publisher, not affiliated with, sponsored by, or endorsed by NGA Center or CCSSO. Every product is sold on Teachers Pay Teachers.