-89.59% is the change from 490 to 51
Calculation steps:
[( 51 - 490 ) ÷ 490] x 100 = -89.59%
Formula
Percentage change = [(51 - 490) / 490] x 100
Subtract the new number by the original number
51 - 490 = -439
-439 ÷ 490 = -0.8959183673469387
-0.8959183673469387 x 100 = -89.59%