Round numbers using Open Number Lines. 1. Click the add response button to start your work. Click drawing to create a workspace. 2. Draw two or three cards to create a two or three digit number. 3. Use the label tool to type the number on your workspace. 4. Use the record tool and pen tool to create a number line. Explain your thinking as you work. 5. :highlight: Highlight the answer on your number line. 6. Remember to click the check to save your work.