Chapter 4.6, Problem 7P

a. Use the partial-products and common methods to calculate $27\times 28.$

b. On graph paper, draw an array for $27\times 28.$ If graph paper is not available, draw a rectangle to represent the array rather than drawing 27 rows with 28 items in each row. Subdivide the array in a natural way so that the parts of the array correspond to the steps in the partial products method.

c. On the array that you drew for part (b), show the parts that correspond to the steps of the common method.

d. Solve $27\times 28$ by writing equations that use expanded forms and the distributive property. Relate your equations to the steps in the partial-products method.