-90% is the change from 540 to 54
Calculation steps:
[( 54 - 540 ) ÷ 540] x 100 = -90%
Formula
Percentage change = [(54 - 540) / 540] x 100
Subtract the new number by the original number
54 - 540 = -486
-486 ÷ 540 = -0.9
-0.9 x 100 = -90%
Example