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# Closures

I think I don't understand what the question is asking. Can someone help me with this? I tried to let the function take in another function but it doesn't seem to work either.

higherOrderFunctions.swift
```/**
For this code challenge, let’s define a math operation as a function that
carries out some work on two integers and returns an integer as well. An
example is the function below, `differenceBetweenNumbers`, which takes two
integers and calculates the difference between the numbers. After calculating,
it returns the difference.
*/

func differenceBetweenNumbers(a: Int, b:Int) -> (Int) {
return a - b
}

func mathOperation () -> (Int, Int) -> (Int) {
return differenceBetweenNumbers
}
``` MOD

Here is a code example from the docs:

```func printMathResult(mathFunction: (Int, Int) -> Int, a: Int, b: Int) {
println("Result: \(mathFunction(a, b))")
} 