## Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

### Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today. # I can't figure out where to put the tax percentage.

We need to figure out the tax amount when the tax percentage is 7.5 percent. Call the method calculateTaxes on the variable item and assign the result to a new variable named taxes.

struct.swift
```struct Expense {
var description: String
var amount: Double = 0.0

init (description: String) {
self.description = description

}
// add the calculateTaxes method here
// it should accept only one parameter named 'percentage' of type Double

func calculateTaxes (percentage: Double) -> Double {
return (self.amount * (percentage/100))

}
}

var item = Expense(description: "Gains")
item.amount = 100.0

var taxes = Expense.calculateTaxes(item)
``` you're calling the `calculateTaxes()` function on Expense, but you should be calling it on item. Expense is the abstract sctruct, item is the real life instance of an Expense. And then 7.5 is the argument you pass into that function. When you defined this function, you specified that it takes a parameter called percentage which is a Double, and it calculates the taxes based on that number. So inside the parentheses is where you put that number when you call it in real life.
```var taxes = item.calculateTaxes(7.5)