Math.4.NF.B.3 Understand a fraction a/b with a>1 as the sum of fractions 1/b.
Math.4.NF.B.3a Understand addition and subtraction of fractions as joining and separating parts referring to the same whole.
Math.4.NF.B.3b Decompose a fraction into a sum of fractions with the same denominator in more than one way. Use a visual fraction model to justify decompositions.
Math.4.NF.B.3d Solve word problems involving addition and subtraction of fractions referring to the same whole and having like denominators.