Addition and subtraction - Add and subtract multiples of 100 - Presentation

In the first lesson of a series focused on addition and subtraction, students are introduced to the concept of adding and subtracting multiples of 100 from three-digit numbers. The lesson begins with a discussion to clarify what a multiple of 100 is, setting the foundation for the activities to follow. Through a series of engaging activities, students explore base 10 examples to understand the process of combining multiples of 100. They start with simple additions such as combining 1 hundred with 2 hundreds to form 3 hundreds, reinforcing their understanding of the base 10 number system and preparing them for more complex calculations.

Moving on to further activities, students are encouraged to apply their knowledge to a variety of problems, such as adding 3 hundreds to 4 hundreds to make 7 hundreds, and so on. They are also tasked with solving practical problems that involve building and drawing models, writing number sentences, and verbalising their understanding in words. For example, they might calculate that 800 plus 100 equals 900, then represent this visually and in written form. The lesson is designed to build fluency in manipulating multiples of 100, as well as to develop reasoning skills through activities that require students to create their own examples and explain their thinking. This structured approach ensures that students gain confidence in their ability to work with larger numbers in a variety of contexts.