The price of everything?

In Excel Math elementary math curriculum we help kids explore the concept of careful shopping. In fact, schools are encouraged to teach thrift (not greed or covetousness) as a desirable character trait and perspective.

Thrift is:

• The quality of using money and other resources carefully and not wastefully.
• Wise economy in the management of money and other resources
• Frugality
• An association or organization that helps people save money (credit union, bank, etc.)
• From Old Norse, from thrífa "to grasp, get hold of"

In the process of teaching thrift we investigate a variety of concepts:

• price comparisons
• determining unit prices (if N items cost $X.XX, how much is one item?)
• reverse unit pricing (if one item costs $X.XX, how many items do you get for $Y.YY)
• the razor and the blade pricing (printer is free but toner is expensive)
• quantity discounts and bulk buying
• reading advertising and sales materials
• common discounting techniques (percentage off the list price, 2 for 1, etc.)
• calculating sales tax
• how interest is charged on loans
• how interest is paid on deposits
• not spending more than you have in your bank account (no deficit spending)
• additional, after-purchase costs (energy consumed, maintenance, repairs, etc.)
• tipping or gratuities

We mention profit and loss too, even though 3rd grade math class is not designed to teach economics. We avoid things like subscriptions, airline tickets, rental cars, used items, negotiation strategies, etc. These limitations are not necessarily based on the youthfulness and inexperience of our students. We just don't have enough time. In reality, there are SO MANY THINGS we might buy that NO ONE can possibly understand all the options.

Here are some numbers shared in a recent TED speech by economists Tim Harford and Cesar Hidalgo.

Tim suggested that for many centuries, our brains needed to compare 300+ items, yet now we are faced with 10,000,000,000 potential choices. Whether this number is accurate or not, we generally only have time to study for a purchase just before we buy that item. We cram. And sometimes we later end up with buyer's remorse.

Once our students understand a bit about the items they want and their prices, they have to complete an exchange with the merchant. The price is usually X plus taxes Y which becomes total Z with possibly an additional tip A.

Depending on their funds, students can use one or more payment methods:

• coins
• bills
• check
• cash card
• debit card
• credit card
• gift certificate
  
• purchase order 
• traveler's check
• put it on account

We don't have the time or ability to get into all these items in detail but we provide an introduction for students. I'll give some examples tomorrow.