MA.CC.4.NF. Number and Operations-Fractions
Build fractions from unit fractions by applying and extending previous understandings of operations on whole numbers.
4.NF.3. Understand a fraction a/b with a > 1 as a sum of fractions 1/b.
4.NF.3.a. Understand addition and subtraction of fractions as joining and separating parts referring to the same whole.
4.NF.4. Apply and extend previous understandings of multiplication to multiply a fraction by a whole number.
4.NF.4.a. Understand a fraction a/b as a multiple of 1/b. For example, use a visual fraction model to represent 5/4 as the product 5 * (1/4), recording the conclusion by the equation 5/4 = 5 * (1/4).