diff --git a/Day_11.js b/Day_11.js
index e69de29..1b82863 100644
--- a/Day_11.js
+++ b/Day_11.js
@@ -0,0 +1,13 @@
+// write a function to takes a number as input and return sum of its digits
+
+function digSum(n){
+    let sum=0;
+    while(n>0){
+        let r=n%10;
+        sum+=r;
+        n=Math.floor(n/10);
+    }
+    return sum;
+}
+console.log(digSum(10154));
+