percent change: shows the change as a percent of the old value ... so divide by the old value and make it a percentage
example: the percentage change from 5 to 7 is: 2/5 = 0.4 = 40%
and percent error: shows the error as a percent of the exact value ... so divide by the exact value and make it a percentage:
example:65/325 = 0.2 = 20%
hope this helps!!