Addition and subtraction - Subtract with two-digit numbers not crossing 10 - Presentation

In a comprehensive lesson on subtraction, students are taught how to subtract two-digit numbers without crossing the ten. The lesson emphasises the importance of correctly setting out calculations for column subtraction. Pupils engage in a series of activities that begin with subtracting numbers such as 78 minus 34. They break down the problem by subtracting ones from ones and tens from tens, leading to an understanding of the resulting tens and ones in their answers. This step-by-step approach ensures that students grasp the concept of subtraction by individual place value, which is a fundamental skill in mathematics.

The lesson progresses with more complex examples, such as subtracting 47 from 31, where students continue to apply their knowledge of place value. They are encouraged to partition numbers into tens and ones, subtract these parts separately, and then recombine them to find the final answer. This methodical partitioning is applied to various problems, reinforcing the concept of subtraction without crossing tens. Additionally, the lesson includes reasoning questions where students determine the difference in quantities, such as the number of stickers one child has compared to another, using subtraction or counting methods. Independent work tasks are designed to further solidify their understanding, as they partition numbers, solve calculations, and explain their methods and thinking behind each step.