387.5% is the change from 80 to 390
Calculation steps:
[( 390 - 80 ) ÷ 80] x 100 = 387.5%
Formula
Percentage change = [(390 - 80) / 80] x 100
Subtract the new number by the original number
390 - 80 = 310
310 ÷ 80 = 3.875
3.875 x 100 = 387.5%
Example