Multiple choice general knowledge science & technology The difference in the numbers painted on either sides of a runway is always '18'. True False Reveal answer Fill a bubble to check yourself A Correct answer Explanation Runway numbers correspond to magnetic compass directions rounded to nearest 10 degrees. Opposing runway ends always differ by 18 (representing 180 degrees opposite directions). For example, runway 09/27 uses 09 for east (90°) and 27 for west (270°).