-21.84% is the change from 824 to 644
Calculation steps:
[( 644 - 824 ) ÷ 824] x 100 = -21.84%
Formula
Percentage change = [(644 - 824) / 824] x 100
Subtract the new number by the original number
644 - 824 = -180
-180 ÷ 824 = -0.21844660194174756
-0.21844660194174756 x 100 = -21.84%