The specific answer is as follows:

1+ 1=2

From additive commutative law's associative law, it can be concluded that when several addends are added, the positions of addends can be exchanged at will; Or add a few addends first and then add them with other addends, and the sum remains the same.

Simple calculation method:

1. In the operation at the same level, the positions of numbers can be exchanged at will, but they should be exchanged with the previous symbols.

2. In the operation at the same level, brackets can be added and removed directly after the plus sign or multiplication sign. Add brackets after minus sign and division sign, delete brackets, and change the symbols in brackets.

3. Make up one method, make up ten methods, make up a hundred methods, and make up a thousand methods: "Make up nine before, make up ten after".