309.64% is the change from 83 to 340
Calculation steps:
[( 340 - 83 ) ÷ 83] x 100 = 309.64%
Formula
Percentage change = [(340 - 83) / 83] x 100
Subtract the new number by the original number
340 - 83 = 257
257 ÷ 83 = 3.0963855421686746
3.0963855421686746 x 100 = 309.64%