The other day, Zoe and I were playing 'store' at the playground. It was my turn to be the customer, and she told me that she had a very big store, so I "should buy many things".
So, I asked for a toothbrush, a pack of gum, some shampoo, lotion, a bottle of water, and 4 rolls of paper towels.
At each request, she went over to an imaginary shelf, and brought me what I requested. When she brought me the paper towels, she counted out, "1, 2, 3 rolls of towels"
I said, "Oh, but I asked for 4 rolls of paper towels"
To which she replied, "Yes, but I only do have 1 more and if I give it to you then my store will not have any more. You may have 3."