In previous lessons, students learned that fractions are built from unit fractions. Here they reason that fractions with the same denominator are composed of parts that are the same size or the same length, so the numerator, which describes the number of parts, determines which fraction is greater. It is important that students have the opportunity to develop this understanding rather than learning a rule about comparing fractions with the same denominator.

Students are reminded that they can use the symbol >, <, or = to record the result of a comparison of fractions, just as they did with whole numbers in earlier grades (MP6). This lesson (including the Cool-down) enables the teacher to gauge students' familiarity with the symbols, but students are not yet expected to rely on the symbols to express comparison.

What prior knowledge about unit and non-unit fractions did you see students use to help them compare fractions?