diff --git a/mapNumRange.md b/mapNumRange.md
new file mode 100644
index 000000000..df12eb8ef
--- /dev/null
+++ b/mapNumRange.md
@@ -0,0 +1,13 @@
+### mapNumRange
+
+Maps a number from one range to another range.
+
+Returns `num` mapped between `outMin`-`outMax` from `inMin`-`inMax`.
+
+```js
+const distance = (num, inMin, inMax, outMin, outMax) => (num - inMin) * (outMax - outMin) / (inMax - inMin) + outMin;
+```
+
+```js
+mapNumRange(5,0,10,0,100); // 50
+```
diff --git a/mapNumRange.test.js b/mapNumRange.test.js
new file mode 100644
index 000000000..77ca11e8d
--- /dev/null
+++ b/mapNumRange.test.js
@@ -0,0 +1,9 @@
+const expect = require('expect');
+const {mapNumRange} = require('./_30s.js');
+
+test('mapNumRange is a Function', () => {
+  expect(mapNumRange).toBeInstanceOf(Function);
+});
+test('Maps 5 to the range 0-100 from 0-10', () => {
+  expect(distance(5,0,10,0,100)).toEqual(50);
+});
diff --git a/tag_database b/tag_database
index 0636ee018..785aa026e 100644
--- a/tag_database
+++ b/tag_database
@@ -179,6 +179,7 @@ longestItem:array,string,utility,intermediate
 lowercaseKeys:object,intermediate
 luhnCheck:math,utility,advanced
 mapKeys:object,function,intermediate
+mapNumRange:math,beginner
 mapObject:array,object,advanced
 mapString:string,array,function,utility,beginner
 mapValues:object,function,intermediate