-93% is the change from 300 to 21
Calculation steps:
[( 21 - 300 ) ÷ 300] x 100 = -93%
Formula
Percentage change = [(21 - 300) / 300] x 100
Subtract the new number by the original number
21 - 300 = -279
-279 ÷ 300 = -0.93
-0.93 x 100 = -93%
Example