Bring a box of name-brand cookies, like Oreos, and the generic equivalent.  The boxes need to be the exact same size and same flavor.  The only difference is the price.

Describe the similarities/ differences between each cookie and each cookie box.  Students are allowed to observe, smell, and taste!

1.     Which cookie box is the better buy? 

2.     What could I do to figure out which is the better buy? 

3.     What are the similarities between the cookie boxes?

4.     What are the differences?

1.     Possibly the generic, depending on the unit price

2.     Divide the total price of each box by the number of cookies per box

3.     Both should have the same amount (mass), same colors, flavors, ingredients

4.     Different price, different number of cookies, one is name brand/generic

1.     Bring out mystery paper towels and chart of absorbency/wet strength results from the previous day.  Tell students that now we’re looking at the math aspect of our experiment- which paper towel is the better buy.

2.     Give the price of each paper towel roll, and help them convert the first price into pennies.  Give the # of sheets per roll for each brand. 

3.     Introduce the term “unit price”- an item’s cost after dividing the total cost by amount of units in a package. 

4.     Distribute Cost Per Sheet worksheet and a calculator to each child.

1.     How did we figure out which cookie was the better buy?

2.      Explain what you could do to find the cost of a paper towel sheet. 

3.     Predict which paper towel you think is the best buy.  Describe what it means to be the best buy.

During their calculations, I can ask-

4.     What other items in the grocery store can they compare this way? 

5.     What items cannot be compared this way? 

6.     Where in the grocery store can you find these calculations? 

7.     Where else could they find competitive prices?

8.     How could this information help you in other shopping departments- like Pets/Electronics/ Clothing, etc.?

1.      With division- dividing the total cost of the cookies by the number of cookies per box

2.     The same procedure- divide the cost per roll by the number of sheets in a roll

Be careful-students might still think they need to look at the roll as a whole and compare prices that way.  Students might also automatically put the larger value on top, when that may not always be the case.

3.      Answers may vary

4.     Anything with multiple items within one package- sodas, fruit snacks, little box cereals; could also work for produce

5.     Things that are a single item- dog toy, milk, yogurt (unless you wanted to get into cost per ounce)

6.     On the item’s description tag under the item- it will tell you unit price, cost per ounce

7.     Sometimes it’s right under the item, but they could also use ads, newspaper, commercials, etc.

8.     Answers may vary- but they could apply it to packs of socks, dog bones, CDs.  They could also compare prices side by side of expensive items, like TVs.

When students have finished calculating, compare numbers (they should all be the same) and create a new column on the wet strength and absorbency results- Cost Per Sheet.  Have the students form an opinion as to which is the best buy.  It’s okay if they don’t all agree- some may prefer the strongest brand no matter what the cost.  Some may prefer the cheapest even though you have to use more of it.  Others may choose brands that are in the middle.

1.     Is there one clear best buy?  What do you prefer in your paper towels- low cost, high absorbency, high wet strength, or a mix?  Are there any brands that we should stay away from?  Evaluate which towel YOU think is the best and defend your decision.

2.     Which would cost more, using 1 “C” towel or 2 “D” towels?  How could we determine if 1 “C” towel is as absorbent /strong as 2 “D” towels?

3.     Connect this information to your paper towel use in real life.  When you use multiple towels to wipe up a small spill, it’s like you are wiping it up with money.  What does this information tell you?

4.     Who would benefit from knowing this information about the paper towels?

1.      Answers may vary.  As long as they can justify their decision with data, count it correct.

Be careful- students might choose a paper towel based on unscientific reasons- it has a pretty color or popular character on it.  Students may ignore the data and intentionally pick the worst buy.

2.     Answers may vary.  Students will need to double the unit price for 2 “D” towels.  Students should also be able to devise an experiment to test absorbency and strength.

3.     Answers may vary.  Students should realize that if they need to clean a spill, they need to be careful not to waste paper towels or use another method.  The more paper towels they waste, the more money they spend to replace them, the more trees cut down needed to make the towels, etc.

4.     Anyone who cleans!  Pet owners, families, janitors, other students- accept any answer as long as it’s reasonable.

Give the students several items and their generic equivalents to find the unit price of.  You could use fruit snacks, pack of sodas, or anything else that has a generic equivalent and comes with multiple items in a package.  Leave some name brands on, and remove some from others.  You could also use ads from rival stores if the ads provided the cost as well as how many were in a package.  Students will fill in their data on the Elaboration page.

Afterward, recap the important points:

·       Unit price is found by dividing the total cost by the number in a package

·       Name-brands usually have higher prices, and use commercials, advertisements, and coupons to get you to buy their products.

·       Generic brands don’t use advertising, usually have lower prices, but there isn’t always a generic product available.

1.     How are you finding the cost per item? 

2.     Discuss advertising- how does it affect which item you might buy.  Connect to commercials and generic’s lack of advertising. 

3.     How do coupons affect an item’s unit price? 

4.     Where do you think stores position their more expensive items?

1.     Dividing the total price by the number of units in a package

2.     Advertisers use cute characters, songs, commercials, etc. to get consumers to buy their brands.  Usually they are more expensive.  Generic does not use advertising, but their prices are usually lower.  However, generic choices are not always available.

3.     Coupons lower the unit price for one time.  Students may not know what to do with the coupon- make sure they subtract it from the total cost before they divide.

4.     Right at eye level when you are looking at the shelf.  Generic products can be above, below, or next to their brand- name counterparts.

Reveal identity of paper towels and any of the mystery items.  Give students the Evaluation page, and have them answer questions as to which item is the best buy.  They need to use the unit price and any pertinent details in their opinion, as well as defend it.  Teachers will collect the sheets for assessment.

1.     Next time you go to the store, what will you do differently? 

2.     When you see a commercial, what do you need to think about? 

3.     How can you use the giant Sunday paper to help you make a decision?

1.     Students should realize that when they see a product, they need to look more closely at the unit price.  If it’s not given, they need to be able to figure it out. 

2.     Is the name brand cheaper or more expensive than the generic? (by finding the unit price)

3.     That is where the coupons and weekly specials are- those can lower name brand unit prices for one time.