How do i...how to subtract a percentage from a number

Quote:

How do i...how to subtract a percentage from a number

As a programmer, you need to be at ease with mathematics. percentages is primary school level.

Quote:

subtract 10% from a number

translate to "number - 10% of number" => "number - (10 / 100) * number"
can also be seen as "number * (1 - 10 / 100 )" => "number * 0.9"

We do not do your HomeWork.
HomeWork is not set to test your skills at begging other people to do your work, it is set to make you think and to help your teacher to check your understanding of the courses you have taken and also the problems you have at applying them.
Any failure of you will help your teacher spot your weaknesses and set remedial actions.
So, give it a try, reread your lessons and start working. If you are stuck on a specific problem, show your code and explain this exact problem, we might help.

As programmer, your job is to create algorithms that solve specific problems and you can't rely on someone else to eternally do it for you, so there is a time where you will have to learn how to. And the sooner, the better.
When you just ask for the solution, it is like trying to learn to drive a car by having someone else training.
Creating an algorithm is basically finding the maths and make necessary adaptation to fit your actual problem.

Hello:
Supose your original variable is x and the result that you want to get is the variable result, then you can use:
result=x*(x>1000?0.9?0.95)

Explanation:
The expresion (x>1000?0.9?0.95) has the following value:
  - 0.9 only if x>1000
  - 0.95 otherwise

So, result has teh following value:
  - x less a 10% of x only if x>1000
  - x less a 5% of x otherwise