Length and height - Subtracting lengths - Presentation

In an engaging lesson on subtracting lengths, students are encouraged to solve practical problems involving the measurement of various objects. The lesson begins with a discussion prompt, inviting pupils to consider what it means to subtract one length from another. They are then presented with a series of activities designed to apply their understanding of subtraction to real-life contexts. For instance, Activity 1 poses a relatable scenario where students must determine how much of a 10-cube-long chocolate bar has been eaten and how many cubes remain. By visualising the chocolate bar before and after some cubes have been consumed, they can easily calculate the difference using subtraction.

The lesson continues with Activity 2, where students compare the trails left by two snails to identify which one is longer. They write subtraction sentences to express the length difference between the trails. A similar approach is taken in Activity 3, where pupils write a subtraction sentence to find the difference in height between two toy houses. Further activities include comparing the heights of sunflowers using paperclips as a unit of measure, and calculating the length of a line of counters both before and after some are removed. The lesson concludes with independent work, where students practice subtracting lengths in various contexts, such as determining the shrinking length of a pencil, comparing the heights of balloons, and the lengths of minibeasts. Throughout the lesson, students are encouraged to discuss key concepts and use appropriate tools to aid their understanding of subtracting lengths.