英文 名字加S 問題

We usually say "the two numbers are different." As for native speakers, it is a bit saturated to say "the number..." are different.

However, grammatically, we use the word"are". It is because there are two numbers. i.e. A and B are different

If you change [is] to [are] in sentence 1, it will become correct.

The [number] of A and B [are] different.

If A and B both stands of not one number, but a few numbers, like
A = 7.5, 8.2, 9.4
B = 7.3, 8.0, 9.1
then sentence 2 is also correct.

The [numbers] of A and B [are] different.

2012-02-15 08:20:52 補充：
即是，都是 "are" 。但第一句對不表示第二句錯。第二句有時亦可以對。如果 A B 是代表一組數時，第二句亦對。