Create own plurals subpackage

fix Typo

plurals/math.go

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2018 DeineAgentur UG https://www.deineagentur.com. All rights reserved.
+ * Licensed under the MIT License. See LICENSE file in the project root for full license information.
+ */
+
+package plurals
+
+type math interface {
+	calc(n uint32) uint32
+}
+
+type mod struct {
+	value uint32
+}
+
+func (m mod) calc(n uint32) uint32 {
+	return n % m.value
+}