-62.03% is the change from 640 to 243
Calculation steps:
[( 243 - 640 ) ÷ 640] x 100 = -62.03%
Formula
Percentage change = [(243 - 640) / 640] x 100
Subtract the new number by the original number
243 - 640 = -397
-397 ÷ 640 = -0.6203125
-0.6203125 x 100 = -62.03%