How do parents of multiple children keep track of them?

THEY DON'T. Or at least, I felt like I hadn't the other day while shopping at Carter's. As I was looking for warm, "feet" 'pajamas for my oldest, I was beginning to feel a little "out of control" of my two boys. At one point, I thought I had lost Matthew. Absolute PANIC came over me, as I shouted to Joseph to look for his little brother. Joseph (the wonderful boy he is) started looking everywhere for Matthew. OMG, what if he ran out of the store? After about 2 minutes of searching, Joseph looked up at me and started laughing. Matthew was ON MY HIP the whole time! Now that is a sign that I had too many children in a short span of time, eh? (Or I may be losing my mind?) HAHA