.position() is off by 0.00001 in Internet Explorer

.position() is off by 0.00001 in Internet Explorer

I have an absolutely positioned div with inline style "top:420px; left:495px;"
The top should of course be equal to 420, and it is:
$('#Achieve').get()[0].offsetTop
       420
$('#Achieve').css('top')
       "420px"

However, grabbing the position yields the following:
$('#Achieve').position()
       [object Object]{left: 495, top: 419.99999618..."}

This is causing math I do to fail because I expect a value of exactly 420.
This behavior does not reproduce in Chrome.