2460% is the change from 25 to 640
Calculation steps:
[( 640 - 25 ) ÷ 25] x 100 = 2460%
Formula
Percentage change = [(640 - 25) / 25] x 100
Subtract the new number by the original number
640 - 25 = 615
615 ÷ 25 = 24.6
24.6 x 100 = 2460%
Example