-90% is the change from 630 to 63
Calculation steps:
[( 63 - 630 ) ÷ 630] x 100 = -90%
Formula
Percentage change = [(63 - 630) / 630] x 100
Subtract the new number by the original number
63 - 630 = -567
-567 ÷ 630 = -0.9
-0.9 x 100 = -90%
Example