Addition and subtraction - Add and subtract multiples of 100 - Planning

In the initial stages of the Autumn Addition and Subtraction unit for Year 3, students are introduced to the concept of adding and subtracting multiples of 100. The National Curriculum objectives are to enhance mental arithmetic skills with three-digit numbers and hundreds, as well as to employ formal written methods for columnar addition and subtraction. Students are also encouraged to estimate calculations and use inverse operations for verification. The unit aims to help pupils solve complex addition and subtraction problems, including those with missing numbers, by applying their knowledge of number facts and place value. Key vocabulary for the unit includes terms like 'addition', 'subtraction', 'multiple', and 'inverse', among others. The lesson utilises interactive Base 10 blocks as a resource, allowing children to visualise and manipulate the numbers they are working with.

The lesson begins with a starter activity, where children recap prior learning and then move on to practical tasks that involve adding and subtracting multiples of 100. They use Base 10 blocks and part-whole models to visualise the numbers and understand the value of each digit in a number. Through guided activities, children learn to articulate their understanding using stem sentences, such as equating the addition of ones, tens, and hundreds. They are encouraged to represent numbers in various ways, including bar models, place value counters, and number lines, and to create their own number stories that correspond to their calculations. As they progress, children explore related facts based on their understanding of place value. The lesson places emphasis on the importance of recognising the place value of digits and understanding that a multiple of 100 always has zeros in the tens and ones columns. The session concludes with a reflective 'Give me five' activity, where students consider what they have learned, the skills they have used, and what they found challenging, ensuring they remember the key points of the lesson.