add up error

例句：

1. 1.The teacher added up the numbers to find out how many students were absent.
   老师把数字加起来，找出缺席的学生人数。
2. 2.The team decided to add up their contributions and donate the money to charity.
   团队决定把他们的贡献加起来，并将钱捐给慈善机构。
3. 3. The manager added up all the expenses and found that there was a shortfall of $500.
   经理把所有费用加起来，发现少了500美元。