9890% is the change from 10 to 999
Calculation steps:
[( 999 - 10 ) ÷ 10] x 100 = 9890%
Formula
Percentage change = [(999 - 10) / 10] x 100
Subtract the new number by the original number
999 - 10 = 989
989 ÷ 10 = 98.9
98.9 x 100 = 9890%
Example