30% is the change from 660 to 858
Calculation steps:
[( 858 - 660 ) ÷ 660] x 100 = 30%
Formula
Percentage change = [(858 - 660) / 660] x 100
Subtract the new number by the original number
858 - 660 = 198
198 ÷ 660 = 0.3
0.3 x 100 = 30%
Example