-10% is the change from 70 to 63
Calculation steps:
[( 63 - 70 ) ÷ 70] x 100 = -10%
Formula
Percentage change = [(63 - 70) / 70] x 100
Subtract the new number by the original number
63 - 70 = -7
-7 ÷ 70 = -0.1
-0.1 x 100 = -10%
Example