v.1. To present the substance of something in a condensed form; summarize something: At the end of the radio program, they sum up the day's news. Here's what I learned—I'll sum it up for you. At the end of the lecture, the professor summed up.
2. To describe or assess something concisely: This poem sums up my feelings perfectly.
3. To add some set of numbers together: The teacher challenged the students to sum up the numbers from 1 to 100 as fast as possible. I wrote down all of our expenses for the week and summed them up.
4. To calculate something, especially by addition: We need to sum up our total costs for this trip. I'm sure this answer is correct—I summed it up myself.