Addition and subtraction - Add a two-digit and ​three-digit number crossing 10 or 100​ - Planning

In a Year 3 mathematics lesson, students are introduced to the concept of adding a two-digit number to a three-digit number with exchanges across tens and hundreds. The lesson uses a range of resources, including a place value chart, base 10 blocks, place value counters, worksheets, and a presentation to support learning. Key vocabulary such as 'place value', 'digit', 'exchange', 'addition', and 'subtraction' are emphasized. The lesson begins with a starter activity where students complete 'fluent in four' questions to recap their previous knowledge. The class teaching input then guides students through the process of representing numbers using place value counters and understanding the significance of exchanging ones for tens and tens for hundreds when adding numbers that cross these boundaries.

Practical activities form the core of the lesson, where students use concrete materials to represent and add numbers, observing and performing exchanges as necessary. For example, they may represent the number of books in a library or the height of a sunflower and then add more to these amounts, exchanging when they accumulate more than ten ones or tens. The importance of zero as a placeholder is also discussed to ensure students understand its role in maintaining the structure of numbers during addition. The lesson includes partner work to discuss the efficiency of different methods and the use of column addition. Common misconceptions such as misplacing the zero, misaligning place value columns, and errors in carrying over are addressed. By the end of the lesson, students aim to be confident in adding numbers with exchanges, using pictorial and practical methods, with more advanced students balancing calculations for greater depth in understanding.