Isn't 6÷2(1+2) the same as saying 6 is divided by everything behind the division symbol such as: 6/2(1+3)

6
___ =

2(1+3)

6
___
2(3) or 2*3

6
_ = 1

6

If you are getting the answer 9, it seems that you are forgetting to simplify. For example: 6÷2*3 is not 3*3, it's 3÷3 or 3/3. When you look at it as a fraction, it should become easier.

6÷2(1+2)same as 6/2(1+2)
6÷2*3 same as 6/2*3
6÷6 same as 6/6. Note: You don't divide 6 by 2 first. Multiply 2 and 3 first then divide. Order of operation still apply.

If you are getting 12 or -4, I don't know what the fuck you are doing.