300% is the change from 80 to 320
Calculation steps:
[( 320 - 80 ) ÷ 80] x 100 = 300%
Formula
Percentage change = [(320 - 80) / 80] x 100
Subtract the new number by the original number
320 - 80 = 240
240 ÷ 80 = 3
3 x 100 = 300%
Example