Feature/math util (#22)

Development supports the math package

mathUtil/floor_example_test.go

@@ -0,0 +1,15 @@
+package mathUtil
+
+import "fmt"
+
+func ExampleFloor() {
+	res1 := Floor(3.14)
+	res2 := Floor(-6.5)
+
+	fmt.Println(res1)
+	fmt.Println(res2)
+
+	// Output:
+	// 3
+	// -7
+}