diff --git a/src/algorithms/math/is_prime.js b/src/algorithms/math/is_prime.js
index 6ec45f1b..0f291bac 100644
--- a/src/algorithms/math/is_prime.js
+++ b/src/algorithms/math/is_prime.js
@@ -5,12 +5,12 @@
  *
  * References: https://javascript.plainenglish.io/11-mathematical-algorithms-in-modern-javascript-bce71318e2da
  */
-const isprime = num => {
-    const limit = Math.floor(Math.sqrt(num));
-    for (let i = 2; i <= limit; i++) {
-        if (num % i === 0) return false;
-    }
-    return num >= 2;
+const isprime = (num) => {
+  const limit = Math.floor(Math.sqrt(num));
+  for (let i = 2; i <= limit; i++) {
+      if (num % i === 0) return false;
+  }
+  return num >= 2;
 };
 
 
diff --git a/src/algorithms/math/sum_all.js b/src/algorithms/math/sum_all.js
index 90fdd430..872775e0 100644
--- a/src/algorithms/math/sum_all.js
+++ b/src/algorithms/math/sum_all.js
@@ -4,14 +4,14 @@
  * @return {Number}  sum sum of the range of numberse
  */
 const sumall = (arr) => {
-    var sum = 0;
-    var min = arr[0];
-    var max = arr[1];
-    for (var i = min; i <= max; i++) {
-        sum += i;
-    }
-
-    return sum;
+  var sum = 0;
+  var min = arr[0];
+  var max = arr[1];
+  var i =0;
+  for (i = min; i <= max; i = i + 1) {
+    sum = sum + i;
+  }
+  return sum;
 };
 
 module.exports = sumall;
diff --git a/src/algorithms/search/naive_search.js b/src/algorithms/search/naive_search.js
index 493fffd6..8177a02f 100644
--- a/src/algorithms/search/naive_search.js
+++ b/src/algorithms/search/naive_search.js
@@ -7,14 +7,14 @@
 
 const naivesearch = (st, pattern) => {
   let count = 0;
-  for (let i = 0; i < st.length; i++) {
-    for (let j = 0; j < pattern.length; j++) {
+  for (let i = 0; i < st.length; i = i + 1) {
+    for (let j = 0; j < pattern.length; j = j + 1) {
       if (st[i + j] !== pattern[j]) break;
-      if (j === pattern.length - 1) count = count + 1;
+      if (j === pattern.length - 1) count += 1;
     }
   }
 
   return count;
-}
+};
 
 module.exports = naivesearch;