80% is the change from 450 to 810
Calculation steps:
[( 810 - 450 ) ÷ 450] x 100 = 80%
Formula
Percentage change = [(810 - 450) / 450] x 100
Subtract the new number by the original number
810 - 450 = 360
360 ÷ 450 = 0.8
0.8 x 100 = 80%
Example