My kindergarten aged daughter is fascinated with her height and we are constantly measuring her height against the wall using a yard stick. Looking at the yardstick, we discussed how the numbers were in sequence from 1 to 10 (and so on). From there, I drew a number line for her to look at. The number line doesn't seem so abstract since we were just talking about the ruler. It seems easier for her to talk about what numbers come before and after others on the number line.