30% is the change from 670 to 871
Calculation steps:
[( 871 - 670 ) ÷ 670] x 100 = 30%
Formula
Percentage change = [(871 - 670) / 670] x 100
Subtract the new number by the original number
871 - 670 = 201
201 ÷ 670 = 0.3
0.3 x 100 = 30%
Example