add in

1. 把……包括在内

If there is going to be a volleyball team, please don't forget to add me in.

要是成立排球队, 请别忘了把我算在里面。

add up

1. 把……加起来

Add up 3, 4 and 5 and you'll get 12.

把三、四、五相加, 总数是十二。

add up to

1. 总计达

The bills add up to exactly $100.

这些帐单加起来正好一百元。

2. 意味着

His evidence really adds up to this: he didn't murder the man.

他的证据实际上意味着:他没有谋杀那个人。