Brian is heading out to lunch. He goes to the bank and withdraws $$30$ from his savings account. He heads to a local tacqueria that sells individual tacos for $$4\mathrm{.}99$ and two tacos for $$7\mathrm{.}99.$ Brian decides that he's hungry enough to eat two tatos, and selects that meal. He pays with a $$10$ bill and tells the cashier to keep the change.

Identify what role money plays in each of the following parts of the story.

Hint: Select each role only once.

Role of Money