-21.48% is the change from 824 to 647
Calculation steps:
[( 647 - 824 ) ÷ 824] x 100 = -21.48%
Formula
Percentage change = [(647 - 824) / 824] x 100
Subtract the new number by the original number
647 - 824 = -177
-177 ÷ 824 = -0.21480582524271843
-0.21480582524271843 x 100 = -21.48%