Lesson 2: The Mystery of 'x'

Starter (10 mins)

The Covered Number

Write a simple equation on the board like "5 + ? = 12". Cover the question mark with a card. Ask students what number is hidden. Repeat with different operations (e.g., "10 - ? = 3", "3 x ? = 15"). Explain that in algebra, we use letters instead of a question mark or a box.

Main Activity (25 mins)

Translating to Algebra

Introduce the term 'variable'. Use the "Variable Vocabulary" handout to define key terms. Work through the first few examples together as a class. Students then work in pairs to translate word problems into simple algebraic expressions.

Example: "I have some apples, and my friend gives me 3 more. Now I have 8." How can we write this using algebra? (a + 3 = 8).

View Handout

Plenary (15 mins)

Algebra in Real Life

Brainstorm situations where we might not know a value. Examples: the cost of an item before you see the price tag, the number of people who will come to a party, the temperature tomorrow. Discuss how we could use a variable to represent these unknown quantities in planning or discussion.