1 plus 1 equals 2, and Arabic numerals have only 1 answers. Because 1 plus 1 is an unchangeable theorem in mathematics, we don't need to go any further, just remember it. But if in the case of computer programming, if expressed in binary.

One plus one may be equal to 10 (binary), and binary is one for each binary. 1 plus 1 equals 10 (binary). There are also some sayings, such as brain teasers, that one plus one may equal three.

If there is no unit.

1 wife plus 1 husband equals 1 family. 1 day plus 1 night equals 1 day. If a tank can hold 4 barrels of water, then 1 barrel water plus 1 barrel water equals half a tank of water. 1 week plus 1 week equals 14 days, 1 month plus 1 month equals 60 days, 1 year plus 1 year equals 730 days, and so on.

There are many such examples. Why can I add 1 to 1 to get so many answers? Because there is a variable that its unit is not completely fixed, it can be used to expand or break one's own mindset.