-10% is the change from 170 to 153
Calculation steps:
[( 153 - 170 ) ÷ 170] x 100 = -10%
Formula
Percentage change = [(153 - 170) / 170] x 100
Subtract the new number by the original number
153 - 170 = -17
-17 ÷ 170 = -0.1
-0.1 x 100 = -10%
Example