-10.36% is the change from 280 to 251
Calculation steps:
[( 251 - 280 ) ÷ 280] x 100 = -10.36%
Formula
Percentage change = [(251 - 280) / 280] x 100
Subtract the new number by the original number
251 - 280 = -29
-29 ÷ 280 = -0.10357142857142858
-0.10357142857142858 x 100 = -10.36%