CCSS.Math.Content.2.G.A.3
The standard
Partition circles and rectangles into two, three, or four equal shares, describe the shares using the words halves, thirds, half of, a third of, etc., and describe the whole as two halves, three thirds, four fourths. Recognize that equal shares of identical wholes need not have the same shape.
Common Core State Standards for Mathematics · Geometry
What this standard means
Students need to split circles and rectangles into 2, 3, or 4 equal parts. They should name the parts as halves, thirds, and fourths, and explain that the pieces together make one whole. They also need to see that equal parts must be the same size, not just similar looking.
Mastery looks like a student drawing fair partitions, naming each share, and saying things like, “Three thirds make one whole.” Common trouble spots are making unequal pieces, thinking fourths must all look the same, or calling any two pieces halves even when one is larger.
Ways to teach it
- Hands-on activity: Give students paper circles and rectangles, then have them fold and cut them into halves, thirds, and fourths.
- Discussion prompt: Show two rectangles split into fourths in different ways and ask, “How can both pictures show fourths?”
- Quick assessment: Ask students to draw a rectangle split into thirds, label one part, and explain how they know the parts are equal.
- Real-world connection: Use a paper pizza menu and ask students to show how two, three, or four friends could share one pizza fairly.
Plan a lesson for CCSS.Math.Content.2.G.A.3
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