diff --git a/FSharp/Calculator/Calc.fs b/FSharp/Calculator/Calc.fs
new file mode 100644
index 0000000..001be20
--- /dev/null
+++ b/FSharp/Calculator/Calc.fs
@@ -0,0 +1,9 @@
+module Calculator
+
+let sum a b = a + b
+
+let subtract a b = a - b
+
+let multiply a b = a * b
+
+let divide a b = a / b
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diff --git a/FSharp/CalculatorTest/TestCalculator.fs b/FSharp/CalculatorTest/TestCalculator.fs
new file mode 100644
index 0000000..f975e0c
--- /dev/null
+++ b/FSharp/CalculatorTest/TestCalculator.fs
@@ -0,0 +1,28 @@
+module TestCalculator
+
+open NUnit.Framework
+open FsUnit
+open Calculator
+
+[<TestFixture>]
+type TestCalculator() =
+
+    [<OneTimeSetUp>]
+    member this.Setup() = printfn "Starting Calculator tests"
+    
+    [<OneTimeTearDown>]
+    member this.TearDown() = printfn "Calculator tests are finished"
+    
+    [<Test>]
+    [<Category("SumTests")>]
+    member this.OneCanSumPositiveIntegers() = Calc.sum 5 5 |> should equal 10
+    
+    [<Test>]
+    [<Category("SumTests")>]
+    member this.OneCanSumNegativeIntegers() = Calc.sum -5 -5 |> should equal -10
+    
+    [<Test>]
+    [<Category("SubtractTests")>]
+    member this.OneCanSubtractPositiveIntegers() = Calc.subtract 5 5 |> should equal 0
+    
+    // Remaining test cases translated similarly
\ No newline at end of file