-76.88% is the change from 640 to 148
Calculation steps:
[( 148 - 640 ) ÷ 640] x 100 = -76.88%
Formula
Percentage change = [(148 - 640) / 640] x 100
Subtract the new number by the original number
148 - 640 = -492
-492 ÷ 640 = -0.76875
-0.76875 x 100 = -76.88%