2947.62% is the change from 21 to 640
Calculation steps:
[( 640 - 21 ) ÷ 21] x 100 = 2947.62%
Formula
Percentage change = [(640 - 21) / 21] x 100
Subtract the new number by the original number
640 - 21 = 619
619 ÷ 21 = 29.476190476190474
29.476190476190474 x 100 = 2947.62%