CPM Homework Banner

Home > AC > Chapter 2 > Lesson 2.1.4 > Problem 2-42


Can zero be represented by any number of tiles?  Using only the unit tiles (in other words, only the and tiles), determine whether you can represent zero on an expression mat with the number of tiles below.  If you can, draw an expression mat demonstrating that it is possible.  If it is not possible, explain why not.

Shaded tile is plus 1.  Tile is negative 1.A blank expression mat with a positive region at the top and a negative region at the bottom.

  1. tiles 

    Two identical tiles in opposite regions will make zero.

    A 2 region Expression Mat. The positive region has 1 positive   unit tile. The negative region has 1 positive unit tile.

    There are other correct solutions.

  1. tiles

    Use the same ideas as in part (a).

  1. tiles

    Could you add a single tile to part (a) and still have zero?

Use the expression mat in the eTool below to determine if zero can be represented.
Click the link at right for the full version of the eTool: 2-42 HW eTool