Question

What is `6 -: 2(1+2)`?

Answer 1

It depends.

Explanation:

If you use PEMDAS strictly, with no embellishments then the answer is `9`

See: https://socratic.org/questions/how-do-you-simplify-6-2-1-2-usind-pemdas

However, there are several arguments for reckoning the result as `1`.

For example, historically the division symbol `-:` called an "obelus" has meant to divide the expression on the left by the expression on the right.

If we followed that line, then:

`6-:2(1+2) = 6/(2(1+2)) = 6/(2*3) = 6/6 = 1`

The bottom line is: If you want to communicate what you mean using symbols and there is potential ambiguity, then add parentheses to make its meaning clear.