400% is the change from 16 to 80
Calculation steps:
[( 80 - 16 ) ÷ 16] x 100 = 400%
Formula
Percentage change = [(80 - 16) / 16] x 100
Subtract the new number by the original number
80 - 16 = 64
64 ÷ 16 = 4
4 x 100 = 400%
Example