+400, +50, 50 - 400, 50 + (-400) = -350
+400, -120, -120 - 400, -120 + (-400) = -520
+400, -75 3/4, -75 3/4 - 400, -75 3/4 + (-400) = -475 3.4
-200, +610, 610 - (-200), 610 + 200 = 810
-200, -50, -50 - (-200), -50 + 200 = 150
-200, -500, -500 - (-200), -500 + 200 = -300
-200, 0, 0 + 200, 0 - (-200) = 200
-200, 120 1/2, 120 1/2 - (-200), 120 1/2 + 200 = 320 1/2
I think this might be the answer.
