This morning, my mother and I went to the market to buy food. It's really lively there, and there are many vegetables, such as cabbage, spinach, carrots and pumpkins. Mother asked her uncle, "How much is a catty of spinach?" Grandpa said, "6 yuan a catty of water spinach." At this moment, my mother said, "Let me test you a question. If you need 9 kilograms of water spinach, how much does it cost? " I said, "6 times 9 equals 54, and a * * * needs 54 yuan money." Mother picked up an egg and said, "How many grams does an egg have?" I thought for a moment, and finally came up with it. I said, "An egg has 15g." Mother said kindly, "son, you are wrong." An egg is about 3g. " I looked down and blushed with laughter.