-40% is the change from 830 to 498
Calculation steps:
[( 498 - 830 ) ÷ 830] x 100 = -40%
Formula
Percentage change = [(498 - 830) / 830] x 100
Subtract the new number by the original number
498 - 830 = -332
-332 ÷ 830 = -0.4
-0.4 x 100 = -40%
Example