## Personal Finance Big Ideas taught in this task: Scarcity

Mrs. Moore’s third grade class wants to go on a field trip to the science museum.

• The cost of the trip is \$245.
• The class can earn money by running the school store for 6 weeks.
• The students can earn \$15 each week if they run the store.
1. How much more money does the third grade class still need to earn to pay for their trip?
2. Write an equation to represent this situation.

## COMMENTARY

The purpose of this instructional task is for students to solve a two-step word problem and represent the unknown quantity with a variable. This task also addresses the concept of scarcity. The students in the 3rd grade class are faced with a scarcity of time – only 6 weeks to earn enough money for the trip. They are also faced with a scarcity of money at the end of the 6 weeks. The teacher can discuss with students the definition of scarcity – not having enough resources to satisfy your wants and possible solutions to this scarcity situation.

This task is part of a set collaboratively developed by Money as You Learn, an initiative inspired by recommendations of the President’s Advisory Council on Financial Capability, and Illustrative Mathematics. Integrating essential financial literacy concepts into the teaching of the Common Core State Standards can strengthen teaching of the Common Core and expose students to knowledge and skills they need to become financially capable young adults. A mapping of essential personal finance concepts and skills against the Common Core State Standards as well as additional tasks and texts will be available at www.moneyasyoulearn.org. This task and additional personal finance-related mathematics tasks are available at www.illustrativemathematics.org and are tagged “financial literacy.”

## Solution

1. We can start by finding out how much money the students can make at the store:

6×15=6×10+6×5=60+30=90

Since

245−90=155

the students still need \$155 dollars for the field trip.

2. We can let n stand for the amount of money they still need. We know that the amount they can make at the store is 6×15 and the amount they need to raise is 245, so one equation is

245−6×15=n

Another possible equation is

6×15+n=245