Unit Plan 21 (Grade 2 Math): Equal Shares—Halves, Thirds, Fourths
Partition circles and rectangles into halves, thirds, and fourths; describe equal shares and the whole, and reason that more equal parts create smaller shares.
Focus: Partition circles/rectangles into 2, 3, or 4 equal shares; describe shares and the whole; reason about the size of shares as the number of parts changes.
Grade Level: 2
Subject Area: Mathematics (Geometry • Math Practices)
Total Unit Duration: 5 sessions (one week), 35–45 minutes per session
I. Introduction
Students explore equal shares by partitioning circles and rectangles into halves, thirds, and fourths. They practice describing one half, one third, one fourth (also called a quarter), explain how two halves/three thirds/four fourths make a whole, and compare the size of shares when shapes are cut into different numbers of equal parts (MP.2).
Essential Questions
- What makes shares equal in a shape?
- How do I name and describe halves, thirds, and fourths?
- Why does the size of each share get smaller as the number of equal shares gets larger?
II. Objectives and Standards
Learning Objectives — Students will be able to:
- Partition circles/rectangles into 2, 3, or 4 equal shares and identify equal vs. unequal partitions.
- Describe shares with words (half, third, fourth/quarter) and explain how many make a whole.
- Reason (MP.2) about why more equal shares of the same whole create smaller pieces.
- Label drawings clearly (share names and whole) and check for equal size shares.
Standards Alignment — CCSS Grade 2
- 2.G.3: Partition circles and rectangles into two, three, or four equal shares; describe shares using the words halves, thirds, fourths; describe the whole as two, three, or four of the shares; recognize that equal shares of identical wholes need not have the same shape.
- Mathematical Practice — MP.2: Reason abstractly and quantitatively (about share size, number of parts, and the whole).
Success Criteria — Student Language
- I can partition shapes into equal shares and tell if they are equal or unequal.
- I can name and describe halves, thirds, and fourths, and explain how many make a whole.
- I can explain why more parts means smaller shares of the same whole.