-83.44% is the change from 640 to 106
Calculation steps:
[( 106 - 640 ) ÷ 640] x 100 = -83.44%
Formula
Percentage change = [(106 - 640) / 640] x 100
Subtract the new number by the original number
106 - 640 = -534
-534 ÷ 640 = -0.834375
-0.834375 x 100 = -83.44%