-83.02% is the change from 642 to 109
Calculation steps:
[( 109 - 642 ) ÷ 642] x 100 = -83.02%
Formula
Percentage change = [(109 - 642) / 642] x 100
Subtract the new number by the original number
109 - 642 = -533
-533 ÷ 642 = -0.8302180685358256
-0.8302180685358256 x 100 = -83.02%