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Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.  # Math commands swift

I'm just playing around, just learned basic functions. I constructed a simple calculator for BMI (body mass index) You should take your height times your height and divide that with your weight to get a BMI value. I'm having problem at row #2. I'm very unsure how i should write..

My code:

1 func dinBmi (weight: Double, length: Double) -> Double {

2 let bmi = (length * length) / weight

3 print(bmi)

4 return bmi

5

6 } Hi Joakim,

You are close to having the right answer. Main issue with your code is that the function is just going to take the function parameter values, perform a calculation and return a value.

When you call the function, you can then assign the function return value to a variable.

So your "let bmi = length * length...etc" should actually occur outside the function (when you call the function). All the function will do is return a value that it calculates from the supplied weight and height.

Here is the code:

```//The function
func calculateBMI(weight: Double, length: Double) -> Double {
return (length * length) / weight
}

//When you want to set a variable to the function output
let myBMI = calculateBMI(weight: 170, length: 60)
```