Place a protractor on a sheet of paper with the curved side facing the top of the paper.
Hold the protractor steady with one hand as you trace the entire curved edge of the protractor onto the paper.
Add measurement markings according to the markings on the protractor. You don't have to mark each measurement on the protractor, but use a uniform set of markings to add to your paper. You might add a dash to your arched number line at each 10 degree mark on the protractor.
Fill in your numbers on the arched number line. The greater the number, the farther to the right it should be. The lesser the number, the farther to the left it should be. Keep the numbers to scale. For instance, if you have 18 evenly spaced dashes on your arched number line, you might have a "1" at the first marking and an "18" at the last marking. If you have negative and positive values, use the top most marking as zero. The negative values will lie to the left of zero, and the positive numbers will lie to the right of zero.