1.2% is the change from 830 to 840
Calculation steps:
[( 840 - 830 ) ÷ 830] x 100 = 1.2%
Formula
Percentage change = [(840 - 830) / 830] x 100
Subtract the new number by the original number
840 - 830 = 10
10 ÷ 830 = 0.012048192771084338
0.012048192771084338 x 100 = 1.2%