The - (subtract) operator takes two numbers, variables, or expressions and subtracts one from the other, thus returning the difference between them. The - operator appears lower in the order of operations than both * and /, so if those appear in an expression, they will be executed first. In addition, the + operator has the same order of operations as -, so the calculator simply executes them left to right in the order that they appear.
:1-1 0 :5→X :2-3X -13 :2→A:3→B :A/B-B/A -.8333333333
- ERR:SYNTAX is thrown if you try to use - (subtract) in place of ‾ (negative). Because they look very similar, it's easy to get this error; at the same time, it's an easy error to fix.