2018年9-12月份雅思口语题库素材（原创）describe an useful skill you learned in the math class

I think the most important skill that I learned in the math class is how to add and subtract, which is really useful. As a basic skill, people always learn it in different ages. Usually, Chinese student learn it in the primary school, which means that after 6 years old. However, my parents thought that it is possible for me to master such skill. Therefore, they taught me that when I was 4 years old. It is an interesting story about how they taught me that. Teachers always tell student how to add or subtract and then give them homework to practice. My parents brought me to the supermarket and taught me to calculate charges. At the beginning, I calculated the number of coins. Then, when I am skillful to do that, I tried to calculate paper money. I was interested in doing that so the process of study was not boring for me. Obviously, add and subtract are useful skills. People who can not do that will meet many difficulties in daily lives.