Unit Plan 24 (Grade 1 Math): Partition Shapes—Halves & Fourths

Focus: Partition circles and rectangles into 2 and 4 equal shares; name shares (half/halves, fourth/quarter) and reason that more equal shares → smaller pieces.

Grade Level: 1

Subject Area: Mathematics (Geometry)

Total Unit Duration: 5 sessions (one week), 45–60 minutes per session

I. Introduction

Students explore equal shares by folding, cutting, and drawing on circles and rectangles. They learn to partition shapes into halves and fourths/quarters, describe each share, and explain why fourths are smaller than halves of the same whole. Real-world contexts (pizza, sandwiches, paper shapes) make “fair share” reasoning concrete.

Essential Questions

• What makes shares equal when we partition a shape?
• How do we name and describe halves and fourths/quarters?
• Why do pieces get smaller when we cut a whole into more equal shares?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Partition circles and rectangles into 2 and 4 equal shares using folds/drawings.
2. Name and describe shares as half/halves and fourth/quarter and use whole ↔ shares language.
3. Decide if a partition shows equal or unequal shares and justify the decision.
4. Explain that with the same whole, more equal shares → smaller pieces (e.g., a fourth is smaller than a half).
5. Use models and words to connect actions (fold, draw, cut) to quantitative ideas about area (MP.2).

Standards Alignment — CCSS Grade 1 (threaded across the unit)

• 1.G.3: Partition circles/rectangles into two and four equal shares; describe shares using half/halves, fourth/quarter; describe the whole as two or four of the shares; recognize that more equal shares means smaller shares.
• Mathematical Practices: MP.2 emphasized (reason quantitatively about the whole and shares); MP.6/MP.7 threaded (precision/structure).

Success Criteria — Student Language

• I can make and spot equal shares in circles and rectangles.
• I can name each share (half, fourth/quarter) and explain the whole ↔ shares relationship.
• I can say why fourths are smaller than halves of the same whole and show it with a model.