660% is the change from 85 to 646
Calculation steps:
[( 646 - 85 ) ÷ 85] x 100 = 660%
Formula
Percentage change = [(646 - 85) / 85] x 100
Subtract the new number by the original number
646 - 85 = 561
561 ÷ 85 = 6.6
6.6 x 100 = 660%
Example