-38.01% is the change from 642 to 398
Calculation steps:
[( 398 - 642 ) ÷ 642] x 100 = -38.01%
Formula
Percentage change = [(398 - 642) / 642] x 100
Subtract the new number by the original number
398 - 642 = -244
-244 ÷ 642 = -0.38006230529595014
-0.38006230529595014 x 100 = -38.01%