-29.11% is the change from 900 to 638
Calculation steps:
[( 638 - 900 ) ÷ 900] x 100 = -29.11%
Formula
Percentage change = [(638 - 900) / 900] x 100
Subtract the new number by the original number
638 - 900 = -262
-262 ÷ 900 = -0.2911111111111111
-0.2911111111111111 x 100 = -29.11%