-69.69% is the change from 640 to 194
Calculation steps:
[( 194 - 640 ) ÷ 640] x 100 = -69.69%
Formula
Percentage change = [(194 - 640) / 640] x 100
Subtract the new number by the original number
194 - 640 = -446
-446 ÷ 640 = -0.696875
-0.696875 x 100 = -69.69%