The correct way is -18 -67. Brackets Parentheses Brackets are symbols used in pairs to group things together. Parentheses or round brackets.
Parentheses Used in an expression for specifying that the sub-expression between the parentheses has to be considered as a single entity.
Parentheses and brackets in math. Adding and subtracting is the LAST step in a calculation. In math parentheses are often used to group together parts of an expression. Parentheses inside of other parentheses are called nested parentheses.