Understand a fraction a/b with a > 1 as a sum of fractions 1/b (e.g., 3/8 = 1/8 + 1/8+ 1/8). Understand addition and subtraction of fractions as joining and separating parts referring to the same whole. Decompose a fraction into a sum of fractions with the same denominator in more than one way, recording each decomposition by an equation and justify decompositions (e.g., by using a visual fraction model) (e.g., 3/8 = 1/8 + 1/8 + 1/8; 3/8 = 1/8 + 2/8; 2 1/8 = 1 + 1 + 1/8 = 8/8 + 8/8 + 1/8). Add and subtract mixed numbers with like denominators (e.g., by using properties of operations and the relationship between addition and subtraction and by replacing each number with an equivalent fraction). Solve word problems involving addition and subtraction of fractions referring to the same whole and having like denominators (e.g., by using visual fraction models and equations to represent the problem).

Number and Operations—Fractions

Build fractions from unit fractions by applying and extending previous understanding of operations of whole numbers.