Other forms: sums; summed; summing
When you determine the sum, you add up all the numbers. When you sum something up, you focus on all of its important points.
The word sum can also refer to a certain amount of money. A new car might cost you a huge sum of money. But if you sum or add up all its benefits, you might be able to justify spending so much. You calculate the total on a restaurant bill when you sum up the prices of everything you ordered. Sum doesn't have to refer strictly to numbers. When you sum something up, you're giving an overview or general statement about it.