The number line should be broken into segments. Whether each represents 1, 2, or 5. You can multiply 5 by 2 simply by taking the value of 5 and multiplying that segment by 2. (So if the value of one segment is 5, the answer is 2 segments. Or if the value of the segment is 1, then the answer is ten segments.) kinda confusing but I hope that helps.
