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Author: Brigid Del Carmen
Categories: Middle School, Math

One way to make variables and expressions more concrete for middle school students is to use real-world examples. Using items around your house, create a “store” and set up expressions to represent the cost of the items. It takes just a few minutes to set up, but this activity will have lasting effects. Those once abstract and confusing variables and expressions will now represent real-world thinking – and real-world shopping!

 

Materials:

  • sticky notes

  • black marker
  • household items, such as books, playing cards, paper clips, cucumbers, apples
  • paper/pencil
  • clipboards (optional)

 

Steps:

  1. Set out several household items (1 of each) and label each with a variable and a price (on sticky notes).

For example:

(b) book = $10.00

(n) napkin = $.25

(y) playing cards = $1.00

(a) apple = $.90

(p) paper clips = $.10

(s) spoon = $2.50

(f) forks = $3.50

(w) water = $1.75

(d) soda can = $1.50

(c) cucumber = $3.50

  1. Begin the activity by explaining to your child that every time you are shopping, especially at the grocery store, you write expressions “in your head”. It’s really simple if you think of writing expressions as just writing out what you are thinking as you shop.

  1. Explain how you would set up a simple expression to represent the cost of one item.

Say: “I want to buy 3 apples.

First, I set up an expression to represent the cost of the apples: 3a

Next, I calculate the cost of the apples by filling in the price of each apple: 3(.90) = $2.70