-30% is the change from 450 to 315
Calculation steps:
[( 315 - 450 ) ÷ 450] x 100 = -30%
Formula
Percentage change = [(315 - 450) / 450] x 100
Subtract the new number by the original number
315 - 450 = -135
-135 ÷ 450 = -0.3
-0.3 x 100 = -30%
Example