671.08% is the change from 83 to 640
Calculation steps:
[( 640 - 83 ) ÷ 83] x 100 = 671.08%
Formula
Percentage change = [(640 - 83) / 83] x 100
Subtract the new number by the original number
640 - 83 = 557
557 ÷ 83 = 6.710843373493976
6.710843373493976 x 100 = 671.08%