Addition and subtraction - Add two three-digit numbers ​crossing 10 or 100​ - Presentation

The lesson on adding two three-digit numbers crossing 10 or 100 is a comprehensive guide to understanding the concept of carrying over in addition. It begins with fluency and reasoning teaching slides that encourage students to think about when and why an exchange of ones and/or tens is necessary during the addition process. The first activity presents a visual representation of adding numbers like 266 and 336, using a place value chart to demonstrate the hundreds, tens, and ones columns. Students are prompted to consider what happens when you accumulate 10 ones and how that affects the other columns.

As the lesson progresses, the activities become more complex, with examples like adding 276 and 346, now involving both 10 ones and 10 tens. Students are asked to observe and explain the process of carrying over in these instances. The lesson also includes column addition exercises with numbers such as 295, 349, and 378, reinforcing the pictorial representations and the concept of regrouping. Real-world problems, such as calculating the total points scored in a game or the total miles driven by two cars, provide practical application of the skills learned. Additionally, reasoning activities challenge students to think critically by rolling dice to create numbers that meet certain criteria, such as being a multiple of 5 or the greatest possible number, and to compare sums without necessarily calculating them, highlighting the importance of place value and number properties.