- (Operator)

is the numerical subtraction operator. There are no surprises, except that subtracting from zero and using the unary - operator yields different results with one particular value: to demonstrate, the following is from interactive Run Mode.

(The value of  cannot be added to zero, have zero added or subtracted from it, be multiplied by one, or be used in other expressions that should be no problem: more details are on the page 524287.999755859375 (Numerical Value).)