Addition and subtraction - Subtract one- from two-digit numbers - Planning

Year 3 students delve into the foundational maths skill of subtracting one-digit numbers from two-digit numbers, with a specific focus on cases where crossing the ten boundary is necessary. This is a crucial component of the National Curriculum objectives, which include mental addition and subtraction of three-digit numbers with ones, tens, and hundreds, and employing formal written methods for three-digit calculations. The lesson emphasises the importance of strong place value understanding, the ability to partition two-digit numbers, and the use of efficient strategies over counting back in ones. Students are introduced to a variety of methods, including using number lines, ten frames, and the formal column method, to enhance their proficiency in subtraction and to grasp the concept of exchanging when there aren't enough ones to subtract a given digit.

The lesson is structured to reinforce learning through a combination of starter questions, class teaching input, independent learning, and a plenary session. Key vocabulary such as 'subtraction', 'exchange', 'tens', and 'ones' is highlighted to strengthen understanding. Students engage in group activities like the exchange game, which simulates the exchange process in a playful yet educational manner. They also work on differentiated worksheets to practice and consolidate their skills. The lesson concludes with a reflective "Give me five" activity, where students evaluate what they've learned, the skills they've used, and the strategies that aided their learning, ensuring they remember the key takeaways from the lesson. Differentiation is provided for varying levels of understanding, from working within 30 using a completed number line to using blank number lines and showing partitioning for those working at greater depth.