$\"\"$

One gallon of water is equal to $\"\"$ cubic inches.

Write an expression.

Phrase: One gallon of water is equal to $\"\"$ cubic inches.

Variable: Let $\"\"$ represent the number of cubic inches of water.

Expressions: $\"\"$ .

Therefore, the algebraic expression is $\"\"$ .

$\"\"$

The algebraic expression is $\"\"$ .