C2.1 Describe how variables are used, and use them in various contexts as appropriate.
Activity 1: Stamp Collection
Summary
In this activity, students represent equality situations in different ways and check if they are true.
Material
- large sheets (one per team)
- markers (one per team)
- sheets of graph paper (one per team)
- coins (enough for each team)
- centicubes (enough for each team)
Action
Present the following situation:
Kaya and her friend go to the Philaterium store to buy stamps to add to their collection. They want to buy stamps from France, Thailand, Qatar and Oman. Here are the values of the stamps.
France = Five cents
Thailand = Ten cents
Qatar = Quarter (twenty-five cents)
Oman = One dollar
Present the following problem:
In the store, Kaya and her friend look at a poster that shows the following:
5 F = 1 Q
9 T + 2 F = 1 O
4 Q + 3 T = 1 O + 6 F
3Q + 5 F = 1 O
- What do the variables represent? Translate each equation into words.
- How can Kaya and her friend check if the equations are true? Explain your reasoning.
Source: adapted and translated from Guide d’enseignement efficace des mathématiques de la maternelle à la 3e année, Modélisation et algèbre, Fascicule 2, Situations d'égalité, p. 181.