diff --git a/src/1week/01.js b/src/1week/01.js
index 7adea99..f2ea0af 100644
--- a/src/1week/01.js
+++ b/src/1week/01.js
@@ -1,7 +1,7 @@
 var x = 2;
 
-function lineFunction() {
-  return 2 * x + 3;
+function lineFunction(xParam = x) {
+  return 2 * xParam + 3;
 }
 
 exports.lineFunction = lineFunction;
diff --git a/src/1week/02.js b/src/1week/02.js
index 439850c..7aaf52d 100644
--- a/src/1week/02.js
+++ b/src/1week/02.js
@@ -1,11 +1,7 @@
-function accumulate(arr) {
-  let accumulator = 0;
-
-  for (let i = 0; i < arr.length; i++) {
-    accumulator += arr[i];
-  }
+const sum = (a, b) => a + b;
 
-  return accumulator;
+function accumulate(arr) {
+  return arr.reduce(sum, 0);
 }
 
 exports.accumulate = accumulate;
diff --git a/src/1week/03.js b/src/1week/03.js
index 9df4e55..893cf55 100644
--- a/src/1week/03.js
+++ b/src/1week/03.js
@@ -1,10 +1,14 @@
-function multiDimensionalAccumulate(multiDimensionalArr) {
+function multiDimensionalArrayCondition ({row, column}) {
+  return column < row;
+}
+
+function multiDimensionalAccumulate(multiDimensionalArray) {
   let accumulator = 0;
 
-  for (let i = 0; i < multiDimensionalArr.length; i++) {
-    for (let j = 0; j < multiDimensionalArr[i].length; j++) {
-      if (j < i) {
-        accumulator += multiDimensionalArr[i][j];
+  for (let i = 0; i < multiDimensionalArray.length; i++) {
+    for (let j = 0; j < multiDimensionalArray[i].length; j++) {
+      if (multiDimensionalArrayCondition({row: i, column: j})) {
+        accumulator += multiDimensionalArray[i][j];
       }
     }
   }
diff --git a/src/1week/04.js b/src/1week/04.js
index a7dd09a..5a48ac6 100644
--- a/src/1week/04.js
+++ b/src/1week/04.js
@@ -1,15 +1,17 @@
-function convertToConditionalUpperCase(words) {
-  let capitalized = [];
+function convertUpperCase(stringParam) {
+  return stringParam.toUpperCase();
+}
+
+function convertLowerCase(stringParam) {
+  return stringParam.toLowerCase();
+}
 
-  for (let i = 0; i < words.length; i++) {
-    if (words[i].length > 5) {
-      capitalized.push(words[i].toUpperCase());
-    } else {
-      capitalized.push(words[i].toLowerCase());
-    }
-  }
+function isLongWord(word) {
+  return word.length > 5;
+}
 
-  return capitalized;
+function convertToConditionalUpperCase(words) {
+  return words.map(word => isLongWord(word) ? convertUpperCase(word) : convertLowerCase(word));
 }
 
 exports.convertToConditionalUpperCase = convertToConditionalUpperCase;