Adding Ten: Place Value Shifts and Number Names

Section role: This presentation supports the 'Mapping the Tens and Words' section, where the teacher brings the class together to formalize the rules of adding 10 and writing number names, drawing on student findings from the previous activity. The teacher will use these slides to illustrate concepts and guide discussion. Slide outline: (1) Title Slide: 'Adding 10: The Tens Digit Mystery' – Introduce the session’s focus on the 'tens' digit when adding 10 and how we write these numbers. (2) Place Value Review: 'What are Hundreds, Tens, and Units?' – Visually display the place value columns using a number like 153, breaking it down into 1 Hundred, 5 Tens, 3 Units. (3) Adding 10: 'The Shifting Tens' – Show an example like 153 + 10 = 163. Highlight that only the tens digit changes, with an arrow pointing to the 5 changing to a 6. (4) The '9 Tens' Challenge: 'What Happens at the Top of a Hundred?' – Illustrate 293 + 10 = 303, clearly showing how the tens digit 'rolls over' and affects the hundreds digit, with 9 tens changing to 0 tens and the hundreds digit increasing. (5) Naming Rule: 'How Do We Say It?' – Present the formal structure: '[Hundreds Name] hundred and [Tens and Units Name]'. Use 'four hundred and sixty-three' for 463 as a clear example. (6) Common Errors to Avoid: 'Watch Out!' – Highlight common mistakes in number naming, such as forgetting the 'and' (e.g., 'four hundred sixty-three') or misspellings of 'hundred'. (7) Quick Check: 'Your Turn to Explain' – Present a number such as 781 + 10. Ask students to identify the new number and prepare to say its name. This slide sets up for individual practice. Concrete examples, figures, or vocabulary the deck must surface: The numbers 153, 163, 293, 303, 463. Key vocabulary to display: 'Increase', 'Place Value', 'Digit', 'Number Name'. Hooks back to the rest of the lesson: Builds directly on the 'Missing Ten Mystery' activity (Section 2) by formalizing the patterns students may have observed. It sets up the 'Number Architect's Final Check' (Section 4) by providing the explicit rules for both addition and number naming. Closing slide: 'What is the biggest change you noticed when adding 10 to a number today?' – Invites student reflection and prepares them for individual practice.