This is an open question.

Look at the unit, 1 0+ 1 0=2 0, 1+1 =2, 1 pair =3,1pair +65438+. 1 day+1 week =8 days, 1 finger+1 hand = 1 finger,1clicks+1 finger, ...

When the units are unified, people agree that: 1+ 1=2.

It is also possible that =7, = 1 1, =T, = 2, = 10, = Kay, = what, = Ren, = L, = Qi, = 14, =4 1.

In daily life, 1 drip+1 drip, 1 pile soil+1 pile soil, 1 pile soil+/bucket water = 1 pile mud.

In logical operation, 1+ 1= 1.

In binary, 1+ 1= 10.

Goldbach conjecture: Every even number not less than 6 is the sum of two odd prime numbers, that is, "1+ 1=2".

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There are still many answers.