Students need a sound knowledge of common fractions and decimal fractions before learning about percentages. “Percent” simply means “per hundred”, and so each percent is one hundredth.
I frequently remind my students who get confused about percentages that all they have to do is to substitute “hundredths” every time they hear “percent” and it will be easier to recognise what is being referred to. Ten percent is easily seen as one tenth, which can easily be multiplied by another number by dividing by ten.
Remember not to talk about “moving the decimal point”, but rather explain to students that dividing by ten means every digit will have to move to the right one place.
Calculating a discounted price takes two steps: calculating the percentage first, then subtracting that from the original price. With easy examples like those on the worksheets, students should be able to cope without having to write down the intermediate step.