Watch the change
Follow clear arrows as one factor halves and the other doubles.
Visual math · Grades 4-5 · Free to try
Small Lessons.
Big “Aha!” Moments.
Explore visual math lessons and printable practice for grades 4-5. Start with a multiplication move that turns tricky numbers into friendly ones.
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Today's lab note
Same product. Easier numbers.
Learn itSee one move at a time.
Try itGet hints before answers.
Explain itUnderstand why it works.
First complete lesson
Double and Half Multiplication
Turn ×25 or ×50 into multiplication by 100 without changing the product.
Make a prediction
Guess the answer before the final result is revealed.
Practice privately
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Free printable
Double & Half — Try It Sheet
Two printer-friendly pages: one page of guided student practice, plus an answer page with parent tips. Designed to print clearly in black and white on US Letter or A4.
Download the 2-page PDFDOUBLE & HALF48 × 2548 ÷ 2 | 25 × 2
2 pages · PDFFor parents and adult buyers
Keep practicing after the free lesson.
The planned 10-page practice pack adds scaffolded exercises, application problems, error analysis, and worked answers. The current USD 4.99 price is a test hypothesis, not proof of market demand.
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About the lab
Child creativity, parent-managed.
Phoebie can help learn, explain, narrate, and share work after parent review. A parent manages publishing, customer support, business accounts, payments, and every public release.
This first version focuses on one useful math idea instead of pretending to be a complete curriculum.