Elwyn D. answered 02/24/16
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Year-round Geometry teacher including 5 summers of Honors Geometry
I don't know what format you are using for vectors, but if you use a format that translates directly to Cartesian coordinates then the first number is east/west with east as positive. The second number is north/south with north positive.
(10,6) + (-10, -2) = (0, 4)
If you are writing that by hand, you might also draw an arrow over the ordered pair, that way you can distinguish, at a glance, a vector from a point.