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