You’ve got the tricky part of 3 ÷ (1/3) = 9.
However, when you apply the order of operations, it’s better to think of the acronym as BO[DM][AS], since the [DM] and [AS] pairs share the same precedence.
Therefore, when you encounter these, you solve them from left to right.
In the case of addition and subtraction. If you have 9 - 9 + 1 you could think of the subtraction as just adding a negative number instead.
This would give you 9 + (-9) + 1, which should then leads you to the correct answer of 1.
Looking at subtraction in this way also makes something known as ‘the commutative property of addition’ more readily apparent.
e.g.;
9 + (-9) + 1 = 1
(-9) + 9 + 1 = 1
1 + 9 + (-9) = 1
etc.
I hope that clears up how we were get 1 after that final stage of the calculation!