1.)Place students into academically diverse cooperative groups and pass out base 10 manipulatives.
2.)Ask students to build a 15 x 13 rectangle (see 15x13 attachment).
3.)Some students will try building their rectangle using only the small cubes. Walk the floor and ask questions such as: I wonder if there is something larger we could use, I see you built a 10x13 we want a 15x13; is there a way you could add more to one side?
4.)It is important for students to work with their group in order to find their own way of building the rectangle.
5.)Have groups share with the class how they built their rectangle using an interactive whiteboard to model for everyone in the class to see. ( Base 10 Blocks) This website allows students to manipulate base ten blocks online.
6.)Show the class how to break the multiplication problem 15 x13 down into smaller multiplication problems (see partial products).
7.)Ask students if they see where the product 100 is located in their rectangle (students should recognize the 10x10).
8.)Ask students if they see where the products 50, 30, and 15 are located in their rectangle (students should be able to find each grouping within their rectangle).
9.)Now ask students to work together to build and solve the problem 14 x17.
10.)Ask students to draw a diagram of their rectangle on the graph paper and label the different products within the rectangle.
11.)This is a great time to also show the relationship between the area model(rectangle) and the traditional algorithm (ex. four times seven is twentyeight, put down the eight and carry the two).
12.)In closing ask every group to make up a double digit multiplication problem to give to another group as a challenge (Limit the size of the double digit numbers to numbers less than 25).
13.)Groups must first build, graph, and solve their challenge problem correctly before passing their challenge on to another group.
14.)Allow groups an opportunity to share their strategy for solving the challenge problem on the interactive whiteboard (if available).
15.)Have student groups discover real life examples for using this twodigit multiplication problems (e.g. find area of a room to buy carpet, area of wall to buy paint, and how much grass seed to sow your yard).
