3900% is the change from 7 to 280
Calculation steps:
[( 280 - 7 ) ÷ 7] x 100 = 3900%
Formula
Percentage change = [(280 - 7) / 7] x 100
Subtract the new number by the original number
280 - 7 = 273
273 ÷ 7 = 39
39 x 100 = 3900%
Example