3.6.E

Math3rd Grade

The Standard

decompose two congruent two-dimensional figures into parts with equal areas and express the area of each part as a unit fraction of the whole and recognize that equal shares of identical wholes need not have the same shape

Texas Essential Knowledge and Skills for Mathematics

Teacher's field guide

What This Standard Means

What Students Need to Do

Students partition matching shapes into equal-area parts. They label one part as 1/n of the whole and explain why equal shares may have different shapes.

What Mastery Looks Like

Given two same-size rectangles, a student can divide each into four equal-area pieces in different ways. The student labels each piece 1/4 and proves equality by counting grid squares.

Common Misconceptions

Students may call pieces equal because they look similar, even when their areas differ. They may think fourths must have the same shape or label each of four parts 4/1.

How to Assess It

Give students two identical 4-by-4 grid rectangles. Ask them to divide one into four strips and the other into four squares, label each share, and explain why both show fourths.

Lesson moves

Ways to Teach It

  1. Give pairs two identical paper squares; fold one into four strips and the other into four small squares, then label each share 1/4.

  2. Show a striped fourth and a square fourth; ask, “How can both be 1/4 when their shapes differ?”

  3. Play Fraction Match: students pair partition cards showing identical wholes with the same number of equal-area shares but different piece shapes.

  4. Use two same-size sandwiches, cut one into four strips and one into four squares, and compare each person’s share.

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