-67.86% is the change from 840 to 270
Calculation steps:
[( 270 - 840 ) ÷ 840] x 100 = -67.86%
Formula
Percentage change = [(270 - 840) / 840] x 100
Subtract the new number by the original number
270 - 840 = -570
-570 ÷ 840 = -0.6785714285714286
-0.6785714285714286 x 100 = -67.86%