5.NF.4a: Interpret the product a/b ∙ q as a parts of a partition of q into b equal parts; equivalently, as the result of a sequence of operations a ∙ q ÷ b. For example, use a visual fraction model to show (2/3) ∙ 4 = (8/3) and create a story context for this equation. Do the same with 2/3 ∙ 4/5 = 8/15. (In general, a/b ∙ c/d = ac/bd).