-34.96% is the change from 984 to 640
Calculation steps:
[( 640 - 984 ) ÷ 984] x 100 = -34.96%
Formula
Percentage change = [(640 - 984) / 984] x 100
Subtract the new number by the original number
640 - 984 = -344
-344 ÷ 984 = -0.34959349593495936
-0.34959349593495936 x 100 = -34.96%