2.5% is the change from 280 to 287
Calculation steps:
[( 287 - 280 ) ÷ 280] x 100 = 2.5%
Formula
Percentage change = [(287 - 280) / 280] x 100
Subtract the new number by the original number
287 - 280 = 7
7 ÷ 280 = 0.025
0.025 x 100 = 2.5%
Example