-60.37% is the change from 646 to 256
Calculation steps:
[( 256 - 646 ) ÷ 646] x 100 = -60.37%
Formula
Percentage change = [(256 - 646) / 646] x 100
Subtract the new number by the original number
256 - 646 = -390
-390 ÷ 646 = -0.6037151702786377
-0.6037151702786377 x 100 = -60.37%