K-5 friendly lesson
One small step at a time.Read the idea, try the activity, and celebrate each win as you go.

Add 3-Digit numbers using Models (With Regrouping)

🚨 The ultimate block stack! What happens when you have 12 tiny Cubes? You smash them together into a Ten-Rod! What happens if you get 12 Rods?

Do this: Read the concept below, then try the quiz or activity.

Lesson 120 of 186

Concept

Regrouping blocks is how we carry the 1s and 10s.

🎯 The "Upgrade" Strategy: 1. Count the Ones (Tiny Cubes): If you count 10 or more tiny cubes... you must grab exactly 10 of them and UPGRADE them into a single Long Rod! Move the new Rod to the Tens section. 2. Count the Tens (Long Rods): If you count 10 or more long rods... you must grab exactly 10 of them and UPGRADE them into a Giant Square Flat! Move it to the Hundreds section.

Now you just count whatever blocks are left sitting on the table.

Try it

Upgrade the blocks!

Instructions: Imagine counting the blocks. If a section gets 10 or higher, you must upgrade it to the next biggest block!

Problem 1: You have 3 Flats, 7 Rods, and 12 Cubes. * The cubes are over 10! Upgrade 10 of them into a new Rod. * New Rods: 7 + 1 = 8. * Cubes left: 12 - 10 = 2. * Answer: 3 Flats, 8 Rods, 2 Cubes = ___

Problem 2: You have 4 Flats, 13 Rods, and 5 Cubes. * The Rods are over 10! Upgrade 10 of them into a new Flat! * New Flats: 4 + 1 = 5. * Rods left: ___ * Answer: ___

Problem 3: You have 1 Flat, 9 Rods, and 15 Cubes. * Upgrade the 10 cubes! It makes a new Rod. * New Rods: 9 + 1 = 10 Rods. * WAIT! Now the Rods are at exactly 10! You must upgrade again! Upgrade the 10 Rods into a new Flat. * Answer: ___