MONEY 钱, an amount of money

金额，款项:

He owes me a large sum of money .

他欠我一大笔钱。

the sum of ￡4000

那笔 4000 英镑的款项

Bill wants to spend a large sum on modernizing the farm.

比尔想花一大笔钱将农场现代化。

We should be happy to buy it for a modest sum.

要是能花不太多的钱就把它买下来，我们会很高兴。

the sum of sth, the total produced when you add two or more numbers or amounts together

和; 总和，总数:

You will have to pay the sum of the two sets of costs.

你得支付那两笔费用。

greater / more / better etc than the sum of its parts, having a quality or effectiveness as a group that you would not expect from the quality of each member

（总体的作用）大于部分之和，个体相加不如集体的力量大:

The team is greater than the sum of its parts.

球队只有团结起来才最强大。

CALCULATION 计算, a simple calculation by adding, multiplying, dividing etc, especially one done by children at school

简单的计算，算术〔尤指小学生的加减乘除运算〕

do your sums, [informal BrE] to calculate whether you have enough money to do something

算一算是否有足够的钱做某事:

Do your sums first before you decide how much to spend.

算一算再决定要花多少钱。

in sum, [formal] used before a statement that gives the main information about something in a few simple words

总之，简而言之:

In sum, soul music is important to the record industry.

总之，对唱片业来说灵乐十分重要。