85.51% is the change from 345 to 640
Calculation steps:
[( 640 - 345 ) ÷ 345] x 100 = 85.51%
Formula
Percentage change = [(640 - 345) / 345] x 100
Subtract the new number by the original number
640 - 345 = 295
295 ÷ 345 = 0.855072463768116
0.855072463768116 x 100 = 85.51%