Algebra Tiles Expression Models

Read the tiles

Positive and negative algebra tiles show numbers or variables with sign. Usually, a positive tile means a value added, and a negative tile means the opposite value. When you read a model, identify:

1. The type of tile: unit tile or variable tile.
2. The sign of each tile: positive or negative.
3. The total number of each kind of tile.

Translate to an expression

• Positive unit tiles represent +1 each.
• Negative unit tiles represent −1 each.
• Positive variable tiles represent +x each.
• Negative variable tiles represent −x each.

Write the expression by adding the values of all tiles. If there are multiple tiles of the same kind, combine them by counting how many appear.

Simplify

Use combining like terms:

• add positive and negative unit tiles together,
• add positive and negative variable tiles together.

For example, if a model has 3 positive x-tiles and 2 negative x-tiles, the result is x. If it has 4 positive unit tiles and 1 negative unit tile, the result is 3.

Check your answer

Count again to make sure every tile was included and that the final expression matches the signs shown. Your simplified answer should use the fewest terms possible.