Area & Perimeter | Unit Squares, Formulas, Compound Shapes & Garden Problems | Math Unit | Grades 3–5

Area & Perimeter is a complete measurement unit on area and perimeter: eight modules in a 27-page student book, plus a 16-page teacher edition with an eight-lesson sequence, model answers, assessment anchors, sources and an AI disclosure.

Perimeter is the length around a shape; area is the space inside it, counted in unit squares. Students see both on the same rectangle before any formula appears, then learn why centimeters measure a fence and square centimeters measure a carpet, explain where A = a × b and P = 2a + 2b come from, discover that equal areas can have very different borders, split a compound shape, and solve a garden problem about the least border material.

What's Included

• 27-page student book with eight modules
• Every module: explanation, worked example, guided practice and a transfer challenge
• A/B/C tasks: secure terms, apply and explain, transfer
• Sentence starters and partner talk for supported entry
• 16-page teacher edition: teaching rationale and an eight-lesson sequence with timings
• Model answer and assessment anchor (recall · apply · transfer) for every module
• Sources and AI disclosure
• Print-ready PDF (A4; prints on US Letter with fit-to-page)

Module Sequence

1. Border and interior — counting unit lengths and unit squares
2. Understand units — cm for length, cm² for area
3. Explain the area formula — rows of unit squares and multiplication
4. Explain the perimeter formula — adding the sides of a rectangle
5. Same area, different border — side pairs for a fixed area
6. Compound shape — splitting into rectangles
7. Garden problem — least border material for a given area
8. Design and check — designing a shape to given measurements

Students Will Learn To

• distinguish area from perimeter and use the correct units
• explain and apply the area and perimeter formulas for rectangles
• solve problems with compound shapes and fixed areas

Perfect For

• Grade 3–5 math
• Measurement and geometry units
• KS2 maths
• Math centers and small-group reteaching
• Homeschool math

Why Teachers Choose This Unit

• A complete sequence, not a set of loose worksheets
• Every task has a written model answer
• Differentiated so the whole class works on the same goal with different amounts of support
• Illustrations used as discussion prompts, with facts checked against the text or a real model
• Plan 8–12 lessons and teach straight from the PDF

Created with AI assistance: ChatGPT (OpenAI) and Claude (Anthropic). All materials were reviewed and edited by a qualified teacher before publication.

Frequently Asked Questions

Which grade does this fit?

It suits Grades 3–5. In Common Core states it sits closest to the Grade 3 and Grade 4 measurement standards on area and perimeter. No official endorsement is claimed.

Are the units metric?

Yes, the tasks use centimeters and square centimeters. The reasoning carries over directly to inches and square inches.

How long does it take?

Plan eight to twelve lessons, or use the eight modules as stations.

How is it delivered?

As an instant digital download after checkout. Nothing is shipped.