Once, he was called to see a shop selling cotton. At this time, a woman went to buy cotton. Hua is solving a math problem. The woman asked, "How much does a bag of cotton cost?" However, diligent Hua didn't hear it, so she answered the calculated answer. The woman screamed, "Why is it so expensive?" At this time, Hua knew that someone was coming to buy cotton, so he said the price. The woman bought a bag of cotton and left. When Hua was about to sit down and continue to calculate, he found that the toilet paper that had just calculated the problem was taken away by the woman. China is anxious to catch up desperately. A rickshaw master saw it and asked him to drive after it. Later, Hua said shyly, "Aunt, please, please give me back the toilet paper." The woman said angrily, "I paid for this, not you." Hua was in a hurry and said, "How about this! I paid for it. " When Hua reached for money, the woman seemed to be moved by the child. Not only did she not want money, but she also returned the toilet paper to China. At this time, Hua Cai was relieved a little. When he got home, he calculated it again.