Algebra - Formulae - Presentation

In a series of engaging algebra lessons, students delve into the world of formulae, starting with a discussion on what constitutes a formula and how to identify one. They are presented with examples such as 'P = 2l + 2w' and are tasked with discerning which expressions qualify as formulae and which do not. The key to this distinction is understanding that a formula must be able to calculate specific values. The lesson involves a variety of activities where students apply their knowledge, such as substituting values into the given formulae to find the perimeter of rectangles, thereby reinforcing their understanding of algebraic expressions and the practical application of formulae in solving mathematical problems.

The lesson continues with more complex tasks where students use a formula to calculate costs based on consumption, such as 'E = 20 + 1.4k' for the cost of electricity, where 'E' represents the total cost and 'k' the kilowatts consumed. Through these exercises, students learn how to substitute real-world values into formulae to find solutions. Moreover, the lesson addresses reasoning skills by presenting scenarios where students must decide between different interpretations of a formula, such as determining the correct charge for a service using 'Cost in pounds = 15 + 20 x number of hours'. The students also explore the concept of formula representation by converting a rule, such as using five times as much flour as sugar in cake-making, into a mathematical formula 'f = 5s'. The lesson concludes with independent work and discussion prompts that encourage students to think critically about the properties of formulae and their use in various contexts.