Addition and Subtraction - Inverse Operations - Planning

In a Year 5 mathematics lesson, pupils are introduced to the concept of inverse operations within the context of addition and subtraction. This lesson aims to enhance the children's understanding of how these operations are interrelated and to use this knowledge to check the accuracy of their calculations. The class begins with a starter activity where children complete 'fluent in four' questions and review prior learning. The main teaching input involves presenting the children with a subtraction calculation and guiding them to discover the corresponding addition fact. This is visualised using an inverse triangle, which helps to illustrate the connection between the two operations. The lesson emphasises the commutative property of addition and encourages students to apply this understanding to find addition facts that match given subtraction problems. For those finding the concept challenging, additional practice with inverse triangles is provided to strengthen their grasp of forming all possible number sentences.

Further activities include reading and solving word problems that require the application of inverse operations. Children work collaboratively to discuss strategies, such as recording the steps of a number journey as a number sentence and then using the inverse to work backwards and find the starting number. The lesson plan includes group work where students complete reasoning tasks from teaching slides, with discussions aimed at breaking down problem-solving steps and modelling the use of formal written methods. Differentiated worksheets are provided for independent practice, catering to varying levels of understanding, from working towards fluency to achieving greater depth in problem-solving. The lesson concludes with reflection prompts that encourage pupils to consider what they have learned about the relationship between addition and subtraction, the skills they have used, and any difficulties encountered. The lesson also addresses common misconceptions, such as the non-commutative nature of subtraction and the correct formation of number sentences to describe word problems.