2.81% is the change from 640 to 658
Calculation steps:
[( 658 - 640 ) ÷ 640] x 100 = 2.81%
Formula
Percentage change = [(658 - 640) / 640] x 100
Subtract the new number by the original number
658 - 640 = 18
18 ÷ 640 = 0.028125
0.028125 x 100 = 2.81%
Example