diff --git a/Javascript/Numbers/roundNumber.js b/Javascript/Numbers/roundNumber.js
new file mode 100644
index 0000000..24eccb9
--- /dev/null
+++ b/Javascript/Numbers/roundNumber.js
@@ -0,0 +1,10 @@
+// Round a number based on a given number of digits
+const round = (n, decimals = 0) => {
+  // firstly, check that input is a number or not.
+  if (typeof n !== 'number') {
+    return 'not a number.'
+  }
+  return Number(`${Math.round(`${n}e${decimals}`)}e-${decimals}`)
+}
+
+console.log(round(1.234567, 4))