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Enable to pass the second task in this challenge , the editor is not suggesting any error and the code is working as expected in playground.

var mathFunction: (Int, Int) -> Int = differenceBetweenNumbers let difference = mathOperation(mathFunction,12,3)

AND

let difference = mathOperation(differenceBetweenNumbers,12,3)

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(differenceBetweenNumbers:(Int,Int) -> (Int),a:Int,b:Int) -> (Int)
{
return differenceBetweenNumbers(a,b)
}
var mathFunction: (Int, Int) -> Int = differenceBetweenNumbers
let difference = mathOperation(mathFunction,12,3)
```

MOD

```// The type of “differenceBetweenNumbers" is (Int, Int) - > Int.

/*
- Now that we have a TYPE, we want to create a function that takes in
this TYPE of function as an argument in its parameter.
*/
func mathOperation(anyAddFunc: (Int, Int) -> Int, a: Int, b: Int) -> Int{
```let difference = mathOperation(differenceBetweenNumbers, 2, 1)