1300% is the change from 20 to 280
Calculation steps:
[( 280 - 20 ) ÷ 20] x 100 = 1300%
Formula
Percentage change = [(280 - 20) / 20] x 100
Subtract the new number by the original number
280 - 20 = 260
260 ÷ 20 = 13
13 x 100 = 1300%
Example