-50% is the change from 490 to 245
Calculation steps:
[( 245 - 490 ) ÷ 490] x 100 = -50%
Formula
Percentage change = [(245 - 490) / 490] x 100
Subtract the new number by the original number
245 - 490 = -245
-245 ÷ 490 = -0.5
-0.5 x 100 = -50%
Example