A 20% increase followed by 25% decrease is it same as original less than original or greater than original

N (120/100) ((100-25) / 100)

n (120/100) (75/100)

n (6/5) (3/4)

n (9/10)

Since 9/10<1, this is less than the original amount. (a decrease of 10% or if you prefer the result is 90% of the original amount)

A 20% increase followed by a 25% decrease is a constant 5% decrease. This is less than the original.