-90% is the change from 220 to 22
Calculation steps:
[( 22 - 220 ) ÷ 220] x 100 = -90%
Formula
Percentage change = [(22 - 220) / 220] x 100
Subtract the new number by the original number
22 - 220 = -198
-198 ÷ 220 = -0.9
-0.9 x 100 = -90%
Example