50% is the change from 84 to 126
Calculation steps:
[( 126 - 84 ) ÷ 84] x 100 = 50%
Formula
Percentage change = [(126 - 84) / 84] x 100
Subtract the new number by the original number
126 - 84 = 42
42 ÷ 84 = 0.5
0.5 x 100 = 50%
Example