-85.98% is the change from 642 to 90
Calculation steps:
[( 90 - 642 ) ÷ 642] x 100 = -85.98%
Formula
Percentage change = [(90 - 642) / 642] x 100
Subtract the new number by the original number
90 - 642 = -552
-552 ÷ 642 = -0.8598130841121495
-0.8598130841121495 x 100 = -85.98%