10% is the change from 280 to 308
Calculation steps:
[( 308 - 280 ) ÷ 280] x 100 = 10%
Formula
Percentage change = [(308 - 280) / 280] x 100
Subtract the new number by the original number
308 - 280 = 28
28 ÷ 280 = 0.1
0.1 x 100 = 10%
Example