(i) A number is increased from 125 to 150; find the percentage increase.
(ii) A number is decreased from 125 to 100; find the percentage decrease

i) Original value $=125$
New value $=150$
Increase $=(150-125)=25$
Increase $\%=25/125\times 100=20\%$

ii) Original value $=125$,
New value $=100$
Decrease $=(125-100)=25$
Decrease $\%=25/125\times 100=20\%$