My math teacher is a man, who is not very tall and with a surname of Li. Mr Li is in charge the daily activities of our class. He is usually smile. However he would be very serious when we mess about. The good thing is he always smiles again after criticising us. My math teacher is a man, who is not very tall and with a surname of Li. Mr Li is in charge the daily activities of our class. He is usually smile. However he would be very serious when we mess about. The good thing is he always smiles again after criticising us.