Can someone explain the math in this Actionscript 3.0 code?

[KDM]

I'm following a tutorial but can't this code to work properly for my project.

 

// This all happens around 15 times per second due to looping and frame rate
// Redefine the mouse X position 
myMouseX = Math.round(logos_bg_clip.mouseX);
// Ready the calculations according to where the mouse is
if (myMouseX > 280) {
calcTravelNum = (myMouseX - 280) / 10;
} else if (myMouseX < 220) {
calcTravelNum = (220 - myMouseX) / 10;
}
// Move the menu according to calculations
if (myMouseX <= 250 && sliding_logos.x <= 30) {
sliding_logos.x = sliding_logos.x + calcTravelNum;
} else if (myMouseX >= 250 && sliding_logos.x >= -330) {
sliding_logos.x = sliding_logos.x - calcTravelNum;
}
// Go and play the loop label again, just keeps looping
gotoAndPlay("loop");