2.86% is the change from 840 to 864
Calculation steps:
[( 864 - 840 ) ÷ 840] x 100 = 2.86%
Formula
Percentage change = [(864 - 840) / 840] x 100
Subtract the new number by the original number
864 - 840 = 24
24 ÷ 840 = 0.02857142857142857
0.02857142857142857 x 100 = 2.86%