828.57% is the change from 42 to 390
Calculation steps:
[( 390 - 42 ) ÷ 42] x 100 = 828.57%
Formula
Percentage change = [(390 - 42) / 42] x 100
Subtract the new number by the original number
390 - 42 = 348
348 ÷ 42 = 8.285714285714286
8.285714285714286 x 100 = 828.57%