Addition and subtraction - Subtract with two-digit numbers - Planning​

In this Year 3 mathematics lesson, the focus is on subtracting two-digit numbers, specifically when crossing ten, which requires an understanding of exchange. Key vocabulary such as 'subtraction', 'exchange', 'tens', and 'ones' are introduced to the students. Using a range of resources like chalks, Base 10, place value grids, and worksheets, the children start by completing a 'fluent in four' activity to recap on their previous knowledge. The class is then guided through practical partner work, where they explore the concept of jumping backwards on a number line to subtract and discuss more efficient methods of calculation. Partitioning the numbers into tens and ones to aid in subtraction is a key skill practised in this lesson, with the use of Base 10 and stem sentences to support understanding.

As the lesson progresses, children build on their understanding of place value and partitioning through a series of activities. They move from using concrete manipulatives to pictorial representations and finally to the more formal method of column subtraction. The lesson includes a number story to contextualise the subtraction process, and children are encouraged to use real-life scenarios such as money to relate to the concept. Key questions prompt students to think critically about the steps involved in subtraction, ensuring they understand when and why to exchange. Students are assessed on their ability to apply these methods with varying levels of support, moving from working towards fluency to achieving greater depth. The lesson aims to ensure that children can confidently subtract two-digit numbers, recognise when an exchange is needed, and select the most efficient method to find the difference between numbers.