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

In a Year 3 mathematics lesson, pupils are taught to subtract a two-digit number from a three-digit number, with a focus on understanding and carrying out exchanges across tens and hundreds. The lesson utilises a variety of resources, including place value mats, counters, Base 10 equipment, and worksheets to support the learning process. Key vocabulary such as 'place value', 'digit', 'exchange', and 'subtraction' are introduced to help children articulate their understanding. The class begins with a starter activity, where students answer 'fluent in four' questions to recap previous learning and prepare them for the session's objective. The importance of place value is emphasised as children learn to exchange one ten for ten ones and one hundred for ten tens using concrete materials before transitioning to written column subtraction methods.

Practical activities guide the children through the subtraction process, starting with relatable number stories to contextualise the learning. For instance, they might calculate the number of penguins remaining on an iceberg after some have jumped off. This activity helps children identify key information, choose the correct operation, and understand why building both numbers isn't necessary. As they progress, pupils work in pairs to tackle challenging problems like 104 subtract 25, using Base 10 to visualise the necessary exchanges. Further activities develop fluency and address common misconceptions such as aligning place value columns correctly and using zero as a placeholder. The lesson concludes with independent work, differentiated to cater to various levels of understanding, from those working towards the expected level to those capable of greater depth. Throughout the lesson, children reflect on what they've learned, the skills they've used, and what they found tricky, ensuring they remember the key concepts for future learning.