Having an agreed order of operation helps in that it means less brackets (parentheses) are needed in an expression (making it less messy) to get the same (correct) answer.
To solve an equation it is sometimes helpful to do what to the original operation?
There is no operation for a single number and so there can be no order of operation.
undo
undo the original operation
There are 6 pats in an operation order
order of operation
33.8
Operation Brevity order of battle happened in 1941.
Operation Chahar order of battle happened in 1937.
Order of battle Swatow Operation happened in 1939.
undo
They must follow the order of operation because if they don't, they will not get the same answer.