Example:

This afternoon, my mother and I went shopping in the supermarket.

When we finished buying what we needed, we were about to leave. I saw sausages on the shelf, so I asked my mother to buy some sausages, and my mother agreed. But just a few steps later, I saw a pack of sausages of the same brand and weight on the shelf. There are 65,438+00 pieces in it, at 4.30 yuan each. Should I buy a set meal or one? I hesitated. Suddenly, my mind turned and I understood. I just need to compare and see which one is cost-effective. So I started to calculate: if I buy 10 pieces in retail, each piece costs 40 cents, which is equal to 4 yuan, and the whole package costs 4.30 yuan, which is 30 cents more, so I decided to buy it in bulk. I told my mother about my calculation process.