106.25% is the change from 320 to 660
Calculation steps:
[( 660 - 320 ) ÷ 320] x 100 = 106.25%
Formula
Percentage change = [(660 - 320) / 320] x 100
Subtract the new number by the original number
660 - 320 = 340
340 ÷ 320 = 1.0625
1.0625 x 100 = 106.25%