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

The curriculum for Year 3's Autumn term includes a week dedicated to mastering addition and subtraction, specifically focusing on subtracting one- from two-digit numbers. The national curriculum objectives for this period are comprehensive, covering mental arithmetic involving three-digit numbers and ones, tens, and hundreds, as well as the use of formal written methods for columnar addition and subtraction. Pupils are encouraged to estimate answers, use inverse operations for checking, and solve a variety of problems that require a solid understanding of number facts, place value, and complex addition and subtraction. Key terminology such as 'addition', 'subtraction', 'exchange', and 'inequality symbols' are highlighted to ensure students are familiar with the language of mathematics.

During the week, children will delve into the concept of adding and subtracting hundreds. The class begins with a starter that prompts students to apply their knowledge of adding hundreds, such as combining 300 and 500, and then progress to adding ones and tens, like in the example 234 + 500. This exercise highlights the importance of understanding when the column method may not be the most efficient. Through various activities, children will explore the impact of adding multiples of 100 to a three-digit number, observing that the tens and ones columns remain unchanged. They will engage in practical tasks, such as ordering calculations, and use place value resources to support their reasoning. The lesson aims to clarify common misconceptions, particularly around place value, and to assess understanding at different levels, from working towards basic fluency to achieving greater depth in mathematical reasoning.