diff --git a/index.html b/index.html
index 93e3367..c54dd17 100644
--- a/index.html
+++ b/index.html
@@ -4146,8 +4146,8 @@ <h4>Exercise 33: Improving our mouse drag event</h4>
 									takeUntil(spriteContainerMouseUps).
 									map(function(movePoint) {
 										return {
-											pageX: movePoint.pageX - contactPoint.offsetX,
-											pageY: movePoint.pageY - contactPoint.offsetY
+											pageX: movePoint.pageX + contactPoint.offsetX,
+											pageY: movePoint.pageY + contactPoint.offsetY
 										};
 									});
 							});