This is a question with an open answer.
Look at the units, 1 0 + 1 0 = 2 0 = 0, 1 + 1 = 2, 1 + 1 pair = 3, 1 pair + 1 pair = 4, 1 quarter + 1 year = 5 quarters, 1 finger + 1 hand = 6 fingers, 1 day + 1 week = 8 days, 1 finger + 1 pair of hands = 11 fingers, 1 dozen + 1 = 13,... ...
When the units were unified, it was agreed that 1+1=2.
Also possible =7, =11, =T, =Two, =Ten, =Kai, =Sh, =Ren, =Litre, =Qi, =14, =41, =King, =Non, =Tian, =Old, =Feng, =Two ......
In life, 1 drop of water + 1 drop of water = 1 drop of water, 1 heap of dirt + 1 heap of dirt = 1 heap of dirt, 1 heap of dirt + 1 bucket of water = 1 heap of mud ......
Logical operations, 1 + 1 = 1
In binary, 1 + 1 = 10
Goldbach's Conjecture: every no less than 6 Every even number not less than 6 is the sum of two odd prime numbers, i.e. "1+1=2".
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There are many more answers.