Length and Perimeter - Equivalent Lengths mm & cm​ - Planning

In the Year 3 Spring term, students embark on a journey to understand the equivalence between millimetres and centimetres in the context of measuring length and perimeter. The lesson commences with a recap of previous knowledge, reinforcing the concept that 10mm is equivalent to 1cm. This foundational understanding is critical as students tackle the conversion of lengths in multiples of 10mm to centimetres and vice versa. Key vocabulary such as 'length', 'centimetre', 'millimetre', 'convert', and 'equivalence' are introduced to enrich the children's mathematical lexicon. A variety of resources including worksheets, presentations, rulers, and classroom objects support the learning process, while a 'fluent in four' questions starter sets the stage for the day's learning.

During the class, students engage in activities that hone their skills in measuring and converting lengths. They examine rulers, identifying the intervals that represent millimetres and understanding the significance of the longer lines that indicate centimetres. Partner discussions encourage collaborative learning as students calculate lengths in millimetres and centimetres, using marked intervals on rulers. Practical tasks involve measuring classroom objects and recording these measurements in both units, emphasising the correct use of the ruler starting at the 0 mark. Further activities challenge students to partition measurements into cm and mm, employing stem sentences to articulate their thought processes. Towards the end of the lesson, reasoning tasks are introduced to address any misconceptions, and differentiated worksheets are provided for independent practice. The lesson concludes with a reflective 'Give me five' exercise, where students summarise what they have learned and the skills they have utilised, ensuring they remember key points, such as the importance of correct ruler alignment and accurate counting.