Unit Plan 33 (Grade 2 Math): Arrays & Equal Shares—From Tiles to Stories

Focus: Use arrays, rows, and columns to represent contexts; express totals as equal addends; connect arrays to partitions and equal shares.

Grade Level: 2

Subject Area: Mathematics (Operations & Algebraic Thinking • Geometry)

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

I. Introduction

Students build and read arrays (up to 5 by 5), write totals as repeated addition, and connect arrays to partitioning rectangles and shapes into equal shares. They explain how the structure of rows and columns (or equal parts) supports clear reasoning in word problems.

Essential Questions

• How do rows and columns help me count quickly and accurately?
• How can I show a total with equal addends or equal shares?
• When I partition a shape into equal parts, what stays the same and what can change?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Build/interpret arrays to find totals and write equations as equal addends.
2. Partition rectangles into rows and columns of same-size squares and count to find totals.
3. Partition shapes into halves, thirds, and fourths; describe the whole and its equal shares.
4. Solve and explain context problems using arrays and partitions, showing MP.2 reasoning (units and quantities).
5. Use models to justify why arrangements or shares are equal and totals are reasonable.

Standards Alignment — CCSS Grade 2 (focus this week)

• 2.OA.4: Use addition to find the total number of objects arranged in rectangular arrays; write an equation to express the total as a sum of equal addends.
• 2.G.2: Partition a rectangle into rows and columns of same-size squares and count to find the total number of squares.
• 2.G.3: Partition circles/rectangles into 2, 3, or 4 equal shares; describe shares and wholes; recognize equal shares need not have the same shape.
• Mathematical Practice: MP.2 (reason abstractly and quantitatively) featured; MP.1, MP.6, MP.7 supported.

Success Criteria — Student Language

• I can build/read an array and write the total as equal addends.
• I can partition shapes into equal shares and explain why they’re equal.
• I can choose a model (array or partition) to solve a story problem and explain my reasoning.