K-5 friendly lesson
Try one idea, then jump into the activity.These lessons are designed to feel short, friendly, and easy to follow.

Use number lines to add three-digit numbers

🐸 Time for some huge leaps! Adding three-digit numbers is easy when you see them on an open number line.

Lesson 1

Concept

A number line isn't just for small numbers. You can use an "open number line" to jump by hundreds, tens, and ones! šŸŽÆ **How to Add on a Number Line:** **Example: 245 + 132 = ?** 1. **Start** with the biggest number on the left side of your line: 245. 2. **Break apart** the second number (132). It has 1 hundred, 3 tens, and 2 ones. 3. **Take a HUGE hundreds jump:** Jump +100 from 245. You land at 345. 4. **Take three tens jumps:** Jump +10, +10, +10 from 345. (355, 365, 375). 5. **Take two tiny ones jumps:** Jump +1, +1 from 375. (376, 377). 6. **Your final landing spot is the answer!** So, 245 + 132 = 377.

Try it

Make big jumps to solve these problems! **Instructions:** Imagine the big jumps on a number line to find the sum. **Problem 1:** 400 + 250 * Start at 400. Jump 2 hundreds (500, 600) and 5 tens. * Answer: ___ **Problem 2:** 310 + 104 * Start at 310. Jump 1 hundred and 4 ones. * Answer: ___ **Problem 3:** 125 + 125 * Answer: ___ **Problem 4:** 550 + 212 * Answer: ___