Generally speaking, if the cost of your product is $100 and your mark up is 20%, your selling price after mark up is $120.
But this is not the case if you're using the MU button in a calculator.
You key in 100/20 MU = 125.
So instead of marking up by 20%, it ended up 25%.
Does anyone know the rationale behind this MU button when used in a calculator ?