256.79% is the change from 280 to 999
Calculation steps:
[( 999 - 280 ) ÷ 280] x 100 = 256.79%
Formula
Percentage change = [(999 - 280) / 280] x 100
Subtract the new number by the original number
999 - 280 = 719
719 ÷ 280 = 2.567857142857143
2.567857142857143 x 100 = 256.79%