The total number of people in the school MINUS the number of people singing calligraphy is the number of people dancing, so 150 MINUS 15 and 76 equals 59.
Learning mathematics well gives us not only knowledge, but also a kind of ability and logical thinking ability. With a breakthrough, we can deduce it step by step along our own premises and assumptions. Of course, no matter how wrong the premises and assumptions are, the calculated results will be wrong, but strict mathematical reasoning can ensure the order of the process and the logic of the results. Inconsistency is the most taboo in writing and communication, and learning mathematics well can effectively improve such problems. This ability, including observing experiments, collecting information and logical reasoning, will benefit for life.