285.54% is the change from 83 to 320
Calculation steps:
[( 320 - 83 ) ÷ 83] x 100 = 285.54%
Formula
Percentage change = [(320 - 83) / 83] x 100
Subtract the new number by the original number
320 - 83 = 237
237 ÷ 83 = 2.855421686746988
2.855421686746988 x 100 = 285.54%