$\"\"$

From the figure :

Towers built with two layers should have $\"\"$ cubes, tower built with $\"\"$ layers should have $\"\"$ cubes and towers built with $\"\"$ layers should have $\"\"$ cubes.

$\"\"$

Complete the table :

Records the number of layers in the tower and the number of cubes in the table.

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

Layers	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$
Cubes	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$

$\"\"$

Find the number of cubes in the tower change as the number of layers in the tower increases :

From the table, tell that each layer adds $\"\"$ more cubes.

Notice that, $\"\"$

Each layers add $\"\"$ more cubes to the tower.

$\"\"$

Write a rule that gives the number of cubes in terms of the number of layers in the tower.

Find number of cubes in term of layers :

Let the number of cubes is $\"\"$ .

The number of cubes is $\"\"$ times the number of layers, or $\"\"$ .

Therefore, the number of cubes is $\"\"$ , where $\"\"$ is the number of layers in the tower.

$\"\"$

Towers built with two layers should have $\"\"$ cubes,tower built with $\"\"$ layers should have $\"\"$ cubes and towers built with $\"\"$ layers should have $\"\"$ cubes.

Tabular form:

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

Layers	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$
Cubes	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$

Each layers adds $\"\"$ more cubes to the tower.

The number of cubes is $\"\"$ times the number of layers, or $\"\"$ .